Cannabinoids determination in oral fluid by SPME–GC/MS and UHPLC–MS/MS and its application on suspected drivers

The confirmation of Δ9-tetrahydrocannabinol (THC) in oral fluid (OF) is an important issue for assessing Driving Under the Influence of Drugs (DUID). The aim of this research was to develop a highly sensitive method with minimal sample pre-treatment suitable for the analysis of small OF volumes (100 μL) for the confirmation of cannabinoids in DUID cases. Two methods were compared for the confirmation of THC in residual OF samples, obtained from a preliminary on-site screening with commercial devices. An ultra high performance LC–MS (UHPLC–MS/MS) method and an SPME–GC/MS method were hence developed. 100 μL of the residual mixture OF/preservative buffer or neat OF was simply added to 10 μL of THC-D3 (1 μg/mL) and submitted to the two different analyses: A — direct injection of 10 μL in UHPLC–MS/MS in positive electrospray ionisation (ESI) mode and B — sampling for 30 min with SPME (100 μm polydimethylsiloxane or PDMS fibre) and direct injection by desorption of the fibre in the GC injection port.The lowest limit of detection (LLOD) of THC was 2 ng/mL in UHPLC–MS/MS and 0.5 ng/mL in SPME–GC/MS. In addition, cannabidiol (CBD) and cannabinol (CBN) could be detected in GC/MS equipment at 2 ng/mL, whilst in UHPLC–MS/MS the LLOD was 20 ng/mL.Both methods were applied to 70 samples coming from roadside tests. By SPME–GC/MS analysis, THC was confirmed in 42 samples, whilst CBD was detected in 21 of them, along with CBN in 14 samples. THC concentrations ranged from traces below the lowest limit of quantification or LLOQ (2 ng/mL) up to 690 ng/mL.     

Multiple murder and criminal careers: A latent class analysis of multiple homicide offenders

PurposeTo construct an empirically rigorous typology of multiple homicide offenders (MHOs).MethodThe current study conducted latent class analysis of the official records of 160 MHOs sampled from eight states to evaluate their criminal careers.ResultsA 3-class solution best fit the data (?2LL = ?1123.61, Bayesian Information Criterion (BIC) = 2648.15, df = 81, L² = 1179.77). Class 1 (n = 64, class assignment probability = .999) was the low-offending group marked by little criminal record and delayed arrest onset. Class 2 (n = 51, class assignment probability = .957) was the severe group that represents the most violent and habitual criminals. Class 3 (n = 45, class assignment probability = .959) was the moderate group whose offending careers were similar to Class 2.ConclusionA sustained criminal career with involvement in versatile forms of crime was observed for two of three classes of MHOs. Linkages to extant typologies and recommendations for additional research that incorporates clinical constructs are proffered.     

The neuroendocrine effects of the TASER X26®: A brief report

IntroductionLaw enforcement officers use conducted electrical weapons (CEW) such as the TASER X26^® to control violently resistive subjects. There are no studies in the medical literature examining the effects of these weapons on the human stress response. This is the first study to compare the human stress response to conducted electrical weapons, oleoresin capsicum (O.C.), a cold-water tank immersion, and a defensive tactics drill.MethodsSubjects were randomized to one of the four interventions studied. Subjects received either a 5-s exposure from the TASER X26 CEW with the probes fired into the back from 7 ft, a 5-s spray of O.C., a skin and mucous membrane irritant, to the eyes, a 45-s exposure of the hand and forearm in a 0 °C cold water tank, or a 1-min defensive tactics drill.ResultsAlpha-amylase had the greatest increase from baseline at 10–15 min with the defensive tactics drill. Cortisol had the greatest increase at 15–20 min with O.C. Cortisol remained most elevated at 40–60 min in the defensive tactics drill group.ConclusionsOur preliminary data suggests that physical exertion during custodial arrest may be most activating of the human stress response, particularly the sympathetic–adrenal–medulla axis. This may suggest that techniques to limit the duration of this exertion may be the safest means to apprehend subjects, particularly those at high-risk for in-custody death. Conducted electrical weapons were not more activating of the human stress response than other uses of force.     

Evaluation of the composition of street cocaine seized in two regions of Brazil

This work evaluates cocaine purity and the concentration ranges of adulterants and inorganic constituents for 31 street cocaine samples seized in two different regions of Brazil from July 2008 to May 2010. Cocaine and adulterants, such as caffeine, lidocaine and benzocaine, were quantified by Gas chromatography–mass spectrometry (GC–MS), and the inorganic constituents were determined by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) and ion chromatography (IC). The cocaine concentrations in the samples seized in the Amazonas state (AM samples) ranged from 154 to 978 mg g^? 1, and these samples did not contain any of the adulterants studied. The cocaine concentrations in the samples seized in the Minas Gerais state (MG samples) ranged from 63.9 to 753 mg g^? 1. Caffeine was the main adulterant found in 76% of the MG samples, ranging in concentration from 5.5 to 645.3 mg g^? 1. Lidocaine was found in 66.7% of the MG samples, with concentrations ranging from 16.3 to 576.7 mg g^? 1. Benzocaine was found in only one MG sample, at a concentration of 84.8 mg g^? 1. Fourteen elements were identified by ICP-OES, and a wide variation was observed in the concentrations of Ca, Mg, Na, P, Al, Fe, Mn and Zn. Pearson Product–moment Correlations between the analytes allowed the constituents to be associated with the chemicals used in the manufacturing of cocaine and with some common diluents. The study of the purity of cocaine and the presence and concentration of adulterants and inorganic constituents is important because the latter can have deleterious effects on health.     

Transfer of fibres on the hands of living subjects and their persistence during hand washing

Textile fibres were transferred to the hands of ten living subjects and their persistence was determined after hand washing. Average number of fibres transferred was 300 ± 133 (female 288 ± 92, male 311 ± 163) per 100 cm² hand area in the 100 experiments. However the number of fibres transferred was not gender dependent but individual dependent. The hand texture of subjects was compared with the number of fibres transferred but the relationship was not observed. The number of fibres transferred varied significantly for the 10 repeated experiments performed under the same conditions for the same subject.The subjects were then asked to wash their hands with water. One test group washed their hands with standing water, and the other with running tap water. Afterwards, the number of fibres remaining on the test subjects' hands were investigated. Migration of the fibres on the surface of the observed hands did occur but total loss of transferred fibre after hand washing did not occur. The average number of fibres remaining per 100 cm² hand area was 14 ± 10 (range = 3–72) for hand washing with standing water, and 10 ± 12 (range = 0–79) for washing with running tap water. The results of this study show the possibility of finding fibres on the hands of a person involved in a criminal case even after hand washing before fibre collection.     

Validity of Demirjian and Willems methods for dental age estimation for Malaysian children aged 5–15 years old

BackgroundOne of the most commonly used method for dental age assessment is the method reported by Demirjian and coworkers in 1973. It was later modified by Willems and coworkers whereby they “performed a weighted ANOVA” in order to adapt the scoring system.AimTo evaluate the applicability of Demirjian and Willems methods for dental age estimation for Malaysian children and to correlate the accuracy of the findings with the chronology of tooth development of premolars and second molars.Materials and methodsA total of 991 dental panoramic radiographs of 5–15-year-old Malaysian children were included in the study. The mean Demirjian and Willems estimated ages were compared to the mean chronological age.ResultsThe mean chronological age of the sample was 10.1 ± 2.8 and 9.9 ± 3.0 years for males and females respectively. Using the Demirjian method, the mean estimated dental age was 10.8 ± 2.9 years for males and 10.5 ± 2.9 years for females. For Willems method, the mean estimated age was 10.3 ± 2.8 years males and 10.0 ± 3.0 years respectively.ConclusionsWillems method was more applicable for estimating dental age for Malaysian children. Overestimation in Demirjian method could be due to advanced development of second bicuspids and molars.     

Development and validation of highly selective screening and confirmatory methods for the qualitative forensic analysis of organic explosive compounds with high performance liquid chromatography coupled with (photodiode array and) LTQ ion trap/Orbitrap mass spectrometric detections (HPLC-(PDA)-LTQOrbitrap)

An LTQ-Orbitrap FTMS is a new (hybrid) mass spectrometric (MS) analyzer. It allows for the acquisition of full scan MSⁿ (n-stage fragmentations, n = 1 − n) spectra with the linear ion trap detector (LTQ) at high speed and/or with the Fourier Transform-detector (Orbitrap) with ultra high mass resolution (> 60,000 at m/z < 400 amu) and high mass accuracy (≤ 1 ppm with internal calibration). In addition it may be coupled with liquid chromatography (LC) with photo diode array (PDA) detection.Two methods for the forensic screening and confirmation of all common trace explosives in post-blast residues have been developed on this instrument using atmospheric pressure chemical ionization (APCI). In one run, the nitrogen-containing explosives are analyzed with the combination of “LC-(PDA)-APCI(−)-LTQ MS²/Orbitrap FTMS” (Method 1). In another run, peroxide explosives are analyzed with “LC-APCI(+)-LTQ MS²/Orbitrap FTMS” (Method 2).The performance of both methods has been validated according to procedures defined in the EU COMMISSION DECISION implementing Council Directive 96/23/EC concerning the performance of analytical methods and the interpretation of results (DC 2002/657/EC) and other standards (NEN 17025 and NEN 7777). The methods are highly selective due to the simultaneous utilization of the Orbitrap FTMS and LTQ MS², both of which are highly selective detectors Tested explosive compounds can be detected in the molecular ion form by the Orbitrap analyzer with minimal mass interference in different matrices when using an extremely narrow mass tolerance detection window (≤ 2 ppm). The identification of a detected compound follows an identification point system. Experimental results show that almost all explosive compounds meet the confirmation criteria (minimum 4 points) required for the positive identification by the DC 2002/657/EC.     

Forensic oral imaging quality of hand-held dental X-ray devices: Comparison of two image receptors and two devices

Recently, different portable hand-held and battery-powered dental X-ray units have become available. Especially for forensic odontological purposes, they offer diverse advantages such as for use in disaster areas and crime-scene locations as also in autopsy rooms and mortuaries. For any application, the most important feature of these hand-held devices is the delivered image quality. The aim of this study is to evaluate the radiographic image quality acquired by two portable X-ray devices in combination with two types of image receptors and to compare the findings with the image quality of a standard intra-oral X-ray device.Eleven samples consisting of eight teeth, two dry skeletal specimens and one formalin-fixed mandible part were mounted on blocks for standardised (re)positioning. Radiological images were acquired with two hand-held (AnyRay^® 60 kVp, 0.02–4.00 mAs and NOMAD^® 60 kVp, 0.023–2.277 mAs) and one wall-mounted (MinRay^® 60/70 kVp 0.14–22.4 mAs) X-ray device combined with two image receptor systems (VistaScan^® phosphor storage plate (PSP) and SIGMA^® M CMOS Active Pixel technology sensor). The effect of X-ray source-to-object distance (SOD) was checked at 20 cm in conjunction with object to image receptor distances (OIDs) of 0.8 and 2.5 cm. For each parameter setup, the exposure times were run from low till high. An expert consent statement was achieved by agreement of four expert observers selecting the optimal images based on a developed four point quality rating system. Next, a selection of the images was assembled in a set of 198 observation screens and scored by seven observers. The observation screens were designed to compare observer scores, relations between devices, receptors and OIDs and images obtained from the different devices at equal exposure levels (mAs). All results were statistically analysed.Radiological image quality was significantly higher for phosphor plate compared with the CMOS digital receptor system (p < 0.0001). Furthermore, a significantly superior image quality was obtained for OID = 0.8 than for OID = 2.5 (p = 0.039). A significant difference in image quality between the three devices was also established (p = 0.02). The present study demonstrated the feasibility of portable X-ray systems for forensic odontological applications based on rendering optimal image quality, provided an in vitro guideline of optimal parameter settings and offered a radiological image database usable in further research.     

Genetic variation in a Japanese population,using the multiplex 24 STRs analysis system

Allele frequency distributions for 24 short tandem repeat (STR) loci were determined using the PowerPlex^R Fusion System (Promega) in 407 Japanese samples. The most informative locus among the 22 STR loci, excluding Amelogenin and DYS391, was Penta E (power of discrimination (PD) = 0.98), while the least informative was TPOX(PD = 0.831). The 22 loci combined matching probability (MP) was calculated to be 4.13 × 10⁻²⁶. These parameters indicated the usefulness of this 24 STR analysis in forensic personal identification and parentage testing among Japanese population.     

Determination of amphetamine-type stimulants,ketamine and metabolites in fingernails by gas chromatography–mass spectrometry

A gas chromatography–mass spectrometry (GC–MS) method was developed and validated for the simultaneous qualification and quantification of methamphetamine (MA), amphetamine (AP), 3,4-methylenedioxy-N-methylamphetamine (MDMA), 3,4-methylenedioxy-N-amphetamine (MDA), ketamine (KET) and norketamine (NKT) in fingernails. Fingernail samples (20 mg) were washed with distilled water and methanol, digested with 1.0 M sodium hydroxide at 95 °C for 30 min, and then extracted with ethyl acetate. Extract solutions were evaporated to dryness, derivatized using heptafluorobutyric anhydride (HFBA) at 60 °C for 30 min, and analyzed by GC–MS. The linear ranges were 0.1–20.0 ng/mg for AP, MDMA and NKT, 0.2–20.0 ng/mg for MA and MDA, and 0.4–20.0 ng/mg for KET, with the coefficients of determination (r² ≥ 0.9989). The intra- and inter-day precisions were within 7.1% and 10.6%, respectively. The intra- and inter-day accuracies were ?10.9% to 0.8% and ?4.3% to 4.5%, respectively. The limits of detections (LODs) and the limits of quantifications (LOQs) for each analyte were lower than 0.094 ng/mg and 0.314 ng/mg, respectively. The recoveries were in the range of 72.3–94.9%. The average fingernail growth rates of two subjects for three years and six subjects for two months were 3.12 mm/month and 3.16 mm/month, respectively. The method proved to be suitable also for the simultaneous detection and quantification of MA, MDMA, KET and their metabolites in fingernails.     

Comparison of the three age estimation methods: Which is more reliable for Turkish children?

BackgroundThree atlases—the GÖK, the Greulich–Pyle (GP), and the Tanner–Whitehouse (TW3)—are used frequently for age determination in Turkey. The purpose of this study was to evaluate the applicability of these three methods related to the skeletal age assessment for Turkish adolescents.Materials and methodsThe conventional roentgenograms of the left hands and wrists, elbows, shoulders, and pelvises of 333 healthy Caucasian children (164 females, 169 males) who fit the study and the criteria of each atlas were obtained. The mean differences (± standard deviation [S.D.] in years) between the chronologic age (CA) and the skeletal age (BA), which were obtained by using each age estimation method, were calculated and tested using t-test.ResultsFor girls, the most accurate method was the TW3 (mean differences (d): ?0.21 (p < 0.05)), following by the GP (d: 0.66 (p < 0.001), and the GÖK (d: 2.99 (p < 0.001)). For boys, the most accurate method was the GP (d: ?0.02 (p > 0.05)), followed by the TW3 (d: ?0.18 (p < 0.05)) and GÖK (d: 1.05 (p < 0.001)).Discussion and conclusionsResults show that the TW3 (for girls) and the GP (for boys) methods are more appropriate than the GÖK atlas for estimating the BA. GÖK could be used for boys aged 11–14 years but it should not be used for girls.     

Recovery of human DNA profiles from poached deer remains part 2: Improved recovery protocol without the need for LCN analysis

Although poaching is a common wildlife crime, the high and prohibitive cost of specialised animal testing means that many cases are left un-investigated. We previously described a novel approach to wildlife crime investigation that looked at the identification of human DNA on poached animal remains (Tobe, Govan and Welch, 2011). Human DNA was successfully isolated and amplified from simulated poaching incidents, however a low template protocol was required which made this method unsuitable for use in many laboratories. We now report on an optimised recovery and amplification protocol which removes the need for low template analysis.Samples from 10 deer (40 samples total — one from each leg) analysed in the original study were re-analysed in the current study with an additional 11 deer samples. Four samples analysed using Chelex did not show any results and a new method was devised whereby the available DNA was concentrated. By combining the DNA extracts from all tapings of the same deer remains followed by concentration, the recovered quantity of human DNA was found to be 29.5 pg ± 43.2 pg, 31 × greater than the previous study. The use of the Investigator Decaplex SE (QIAGEN) STR kit provided better results in the form of more complete profiles than did the AmpF?STR® SGM Plus® kit at 30 cycles (Applied Biosystems). Re-analysis of the samples from the initial study using the new, optimised protocol resulted in an average increase of 18% of recovered alleles. Over 17 samples, 71% of the samples analysed using the optimised protocol showed sufficient amplification for comparison to a reference profile and gave match probabilities ranging from 7.7690 × 10^? 05 to 2.2706 × 10^? 14.The removal of low template analysis means this optimised method provides evidence of high probative value and is suitable for immediate use in forensic laboratories. All methods and techniques used are standard and are compatible with current SOPs. As no high cost non-human DNA analysis is required the overall process is no more expensive than the investigation of other volume crime samples. The technique is suitable for immediate use in poaching incidents.     

Analysis of hair after contamination with blood containing cocaine and blood containing benzoylecgonine

In post-mortem work, blood is a potential source of external contamination of hair. The present study was carried out to investigate the amount of drug absorbed into hair which has been contaminated with blood containing either cocaine or BE. Solutions were prepared containing 0.05, 0.1, 0.2, 0.5 and 3.0 μg/mL of either cocaine or BE in human blood. Samples of approximately 3.2 g of drug-free hair were contaminated by soaking in the blood solutions for 5 min. They were then removed and left at room temperature. Approximately 0.5 g of hair was collected from each of the blood soaked hair samples at 6 h, 1, 2, 4 and 7 days after contamination. As each hair sample was collected it was shampoo-washed to prevent further drug absorption. Hair samples were analysed in triplicate using a fully validated method described previously. EME and cocaethylene were also measured in order to find out if cocaine or BE was breaking down to these compounds. Both cocaine and BE were absorbed into hair in significant concentrations when the concentration in the blood was 0.5 μg/mL or greater; cocaine was more readily absorbed than BE. Cocaine broke down to EME (<LOQ) at 0.5 μg/mL and to EME (>LOQ) and BE (<LOQ) at 3.0 μg/mL. When the blood concentration of cocaine was 0.5 μg/mL or less, there was no evidence of it breaking down to form BE. From the samples soaked in blood containing BE, there was no evidence of the BE breaking down. The absorption of drug into hair did not increase as the contamination period increased from 6 h to 7 days.     

Perceptions and experiences of people with mental illness regarding their interactions with police

This study examined the perceptions and lived experiences of people with mental illness in relation to their interactions with the police. A community-based participatory research approach was used and a procedural justice theoretical perspective guided the study. In-depth, semi-structured interviews were conducted by peer researchers with 60 people with mental illness who had interacted with the police and were living in Metro Vancouver, Canada. Among the study participants, contact with the police was frequent and occurred under a diverse range of circumstances. The majority of participants perceived being treated in a procedurally just manner by the police officer(s) who were involved in their most recent interaction. Almost three-quarters (n = 43, 72%) of participants were generally satisfied with how the police officer(s) had handled their most recent interaction. The slight majority of participants (n = 30, 51%) rated their previous contacts with the police as a positive experience overall, with 32% (n = 19) indicating that their previous interactions with the police were negative life experiences. The findings paint a more balanced picture than that which is often portrayed by the media. Emphasizing a procedural justice framework for police handling of situations involving people with mental illness is a vital step toward improving how these interactions are experienced and perceived.     

Age estimation by pulp/tooth area ratio in canines: Cameriere's method assessed in an Indian sample using radiovisiography

Age estimation of an individual whether living or dead is an intimidating task in forensic investigations. Since teeth are more resistant to most peri- and post-mortem changes, they are frequently used for identification and age estimation when skeletal remains are in poor condition. However, most methods are destructive and warrant extraction of teeth which is not feasible in living individuals. Cameriere's et al. put forth a radiographic method of age estimation by pulp to tooth area ratio (AR) in canines and revealed a linear regression between age and the AR. In the present study, we estimated the AR in 456 canines (upper, lower and both) in an Indian sample (114 males and 114 females) using radiovisiography technique. Linear regression equations were derived for upper canine, lower canine and both using the AR to estimate chronological age. Additionally, the efficacy of these equations was also evaluated in younger age group (<45 years). The formulas derived, i.e., age = 96.795 ? 513.561x₁ (Eq. (1)) for upper canine, age = 88.308 ? 458.137x₂ (Eq. (2)) for lower canine and age = 99.190 ? 283.537x₁ ? 306.902x₂ + 400.873x₁x₂ (Eq. (3)) for both the canines were applied to predict the chronological age. The mean value of residuals using these regression equations ranged from 4.28 to 6.39 years with upper canine equation generally giving a precise result. When these equations were applied for younger ages (<45 years), the regression equation derived from both canines gave a better result (mean residual 2.70 years). Overall these equations were better able to predict the age in younger ages, i.e., up to 45 years.     

Detection of acute fentanyl exposure in fresh and decomposed skeletal tissues part II: The effect of dose–death interval

The effects of dose–death interval on the detection of acute fentanyl exposure in fresh and decomposed skeletal tissues (marrow and bone), by automated enzyme-linked immunosorbent assay (ELISA) are described. Rats (n = 14) were administered fentanyl acutely at a dose of 0 (n = 2) or 60 μg/kg (n = 12) by intraperitoneal injection, and euthanized within 20, 45, 135, or 225 min. Femora and tibiae were extracted from the fresh corpses and marrow was isolated from the femoral and tibial medullary cavities. The remains were then allowed to decompose outdoors to the point of complete skeletonization, and vertebrae, pelvi and miscellaneous (humeri and scapulae) were recovered for analysis. In all cases, bones were cleaned in alkaline solution and then ground into a fine powder. Marrow was homogenized in alkaline solution. Fentanyl was extracted from ground bone by methanolic extraction. Extracts were adjusted to pH 6 and analyzed by ELISA. Perimortem heart blood was also collected and diluted in phosphate buffer prior to screening by ELISA. The effect of tissue type on ELISA response was examined through determination of binary classification test sensitivity and the relative decrease in absorbance (%DA, drug-positive tissues vs. drug-free controls) in each tissue type. Overall, the %DA varied significantly between extracts from different skeletal tissues at a given dose–death interval, according to the general order of marrow > decomposed bone > fresh bone. Binary classification test sensitivity values for fentanyl in marrow, fresh epiphyseal (femoral and tibial) bone, fresh diaphyseal (femoral and tibial) bone, decomposed vertebrae, decomposed pelvic bone, and decomposed miscellaneous bone were 67–100%, 0–33%, 0–33%, 0–67%, 0–67% and 0–33%, respectively, over all dose–death intervals. Although group mean %DA values showed a strong negative correlation with dose–death interval in marrow, fresh epiphyseal bone, decomposed vertebrae, pelvic and miscellaneous bone (r = ?0.989, ?0.930, ?0.955, ?0.903, and ?0.974, respectively), the high variability in both fresh and decomposed bone precluded differentiation of the dose–death intervals based on %DA value alone. Overall, the results suggested that the type of skeletal tissue sampled may not be as important as the amount of residual marrow remaining in skeletonized remains.     

Prevalence of blood alcohol in fatal traffic crashes in Shanghai

The objective of this project was to investigate the incidence of alcohol consumption in fatal traffic deaths in Shanghai, one of the largest cities in China. A study was conducted on 803 individuals killed in road accidents during the period 2009–2011, in terms of alcohol-positive rate, mean blood alcohol content (BAC), gender, age, vehicle type, pedestrian alcohol problem, single-vehicle vs multiple-vehicle crashes, and time of day. It was found that 28.9% of the drivers involved had a BAC ≥ 0.20 mg/mL (limit of civil offense) and 21.8% had a BAC ≥ 0.80 mg/mL (limit of criminal offense). The mean BAC of alcohol-positive drivers (with a BAC ≥ 0.20 mg/mL) was 1.51 mg/mL. The vast majority of the drivers involved were males. With regards to age, the largest group was of drivers aged between 40 and 49 years group in both alcohol-negative cases (26.8%) and alcohol-positive cases (26.2%). Motorcycles were most likely to be involved, representing 34.4% of alcohol-negative crashes and 51.6% of alcohol-positive crashes. Very high BACs were common among alcohol-positive pedestrians, yet all female pedestrians were alcohol-negative. Single-vehicle crashes were over-represented in alcohol-positive cases. Alcohol-negative crashes and alcohol-positive crashes most often happened during the time period of 17:00–18:59 and 19:00–20:59, respectively.     

Duplex-specific nuclease (DSN): A method for the rehabilitation of low-copy number DNA profiles

A continual challenge in the field of forensic DNA analysis is the amplification and interpretation of degraded and low-copy number (LCN) DNA obtained from amounts of limited biological evidence. It has been well established that DNA profiles obtained from the amplification of low quality, degraded, and/or LCN DNA samples are often of limited value due to the frequent occurrence of preferential amplification during polymerase chain reaction (PCR). The by-products of preferential PCR amplification are often observed as inter- and intra-locus peak imbalance, allelic dropout, and/or locus dropout. These are all artifacts that are identified during the interpretation phase of analysis rather than by improving the quality of the DNA present. While it is theoretically possible to obtain a complete DNA profile from a single cell, in reality, profiles obtained from suboptimal amounts of DNA are difficult to interpret and frequently inconsistent when replicated. Inspired by advances in next-generation sequencing techniques, we propose a methodology for simultaneously normalizing the abundance of PCR products across all short tandem repeat (STR) loci using the DNA exonuclease, duplex-specific nuclease (DSN). DSN is an enzyme isolated from the hepatopancreas of Red King (Kamchatka) crab that possesses a strong affinity for digesting double stranded DNA (dsDNA) and has limited activity toward single stranded DNA (ssDNA). Degraded DNA known to display peak imbalance and allele dropout was amplified using AmpFlSTR^® Identifiler^® Plus for 28 cycles. Following amplification, samples were denatured at 99.9 °C for 5 min and incubated with one unit of DSN at 62 °C in a 28 μl volume for 1 min. Nuclease activity was terminated through the addition of equal volume of 10 mM EDTA and 95 °C incubation for 2 min. Following DSN treatment, 21 of 30 alleles within the known profile exhibited some improvement in peak height balance. The findings obtained support the potential use of DSN treatment as a method for normalizing STR profiles and improving the quality of data from degraded and low quantity DNA samples.