Applicability of DNA analysis on adhesive tape in forensic casework

Adhesive tape is commonly used in crimes and is often the subject of forensic evaluation. DNA analysis of adhesive tape can provide DNA profiles of suspects. The object of this study was to evaluate the applicability of DNA analysis on adhesive tape samples in forensic casework. We retrospectively reviewed all cases involving adhesive tape or similar items received by our institute for DNA analysis during the past 11 years. From 100 forensic cases reviewed, 150 adhesive tape samples were examined. A total of 98 DNA profiles were obtained from these samples. Sixty-two of the profiles provided feasible case-relevant information. In conclusion, DNA profiling of adhesive tape samples can be useful in a variety of forensic cases.     

Selection of an adhesive tape suitable for forensic fiber sampling

Five commercial adhesive tapes were tested for fiber uptake and saturation, for recovery and for ease of analysis. On the basis of the results, a high tack adhesive tape has been selected to be used for forensic fiber sampling. This adhesive tape is used as sampling material in two different micro trace kits. The first tape lifting kit is used mainly for the sampling of cars and the second is a 1:1 tape lifting kit for the collection of fibers on a corpse.     

Using hydrophilic adhesive tape for collection of evidence for forensic DNA analysis

Known exemplar samples of human DNA have traditionally been body fluids, such as blood, saliva, and semen. In each case, the presence of water is a risk for the bacterial growth, which may degrade the DNA evidence. In this study, the authors have developed a method that employed a hydrophilic adhesive tape (HAT) for collecting DNA evidence. The HAT method was used to remove surface cells from relatively hairless areas on the body. The area examined were ankle, arm, behind the ear, between fingers and back of the neck. The HAT was then dissolved in the extraction buffer. DNA typing was performed at vWA, THo1, F13A1, and FES loci using the short tandem repeat (STR) analysis. Our results show that the samples collected from ear give the best results with a success rate of 100%. All subjects tested by this method had known STR genotypes established from buccal swabs. The authors' results suggest that the HAT method can be used as a less invasive method for collecting biological evidence for forensic DNA analysis. In addition, this collection method should reduce the risk of DNA degradation due to the moisture, which is encountered using conventional collecting methods.     

胶带的红外光谱检验

目的建立胶带的种类检验、方法。方法应用傅利叶显微红外光谱仪,分别对胶带的胶质、基质(基材)及整体(胶质和基质同时存在)进行检测分析。结果不同种类胶带,红外吸收图谱存在差异,相互间图谱匹配率不同。通过比对分析,可对不同种类的胶带进行鉴别。结论该方法检验胶粘带(胶带),检材用量少、结果准确,操作简便,具有很强的实用性。     

Use of nitrogen cryogun for separating duct tape and recovery of latent fingerprints with a powder suspension method

Duct tape is sometimes recovered as physical evidence in crimes. The purpose of this study was to determine the quality of latent prints on the adhesive and non-adhesive surfaces of duct tape samples that were separated using three methods. Three hundred donor fingerprint impressions were deposited on duct tape. Sections of duct tape were affixed to sections of cardboard and a fingerprint placed on the non-adhesive surface of the tape. A second layer of duct tape was prepared and a fingerprint placed on the adhesive side of the tape and then the tape was affixed to the piece of tape on the cardboard. After a 24-h period, the samples were separated using gradual force, liquid nitrogen applied with a cryogun and an adhesive neutralizer to separate the layers of tape. The recovered fingerprints were processed with a fingerprint powder suspension method. The recovered fingerprint images were evaluated and rated as +1, +2, or +3. The liquid nitrogen spray separation method yielded the highest number of +3 prints.     

Nondestructive Biological Evidence Collection with Alternative Swabs and Adhesive Lifters

In forensic science, biological material is typically collected from evidence via wet/dry double swabbing with cotton swabs, which is effective but can visibly damage an item's surface. When an item's appearance must be maintained, dry swabbing and tape‐lifting may be employed as collection techniques that are visually nondestructive to substrates' surfaces. This study examined the efficacy of alternative swab matrices and adhesive lifters when collecting blood and fingerprints from glass, painted drywall, 100% cotton, and copy paper. Data were evaluated by determining the percent profile and quality score for each STR profile generated. Hydraflock^® swabs, BVDA Gellifters^®, and Scenesafe FAST? tape performed as well as or better than cotton swabs when collecting fingerprints from painted drywall and 100% cotton. Collection success was also dependent on the type of biological material sampled and the substrate on which it was deposited. These results demonstrated that alternative swabs and adhesive lifters can be effective for nondestructive DNA collection from various substrates.     

Forensic utility of carbon isotope ratio variations in PVC tape backings

Forensic interest in adhesive tapes with polyvinyl chloride (PVC) backings (electrical tape) derives from their use in a variety of illicit activities. Due to the range of physical characteristics, chemical compositions, and homogeneity within a single roll of tape, traditional microscopic and chemical analyses can offer a high degree of discrimination between tapes, permitting the assessment of potential associations between evidentiary tape samples. The carbon isotope ratios of tapes could provide additional discrimination among tape samples. To evaluate whether carbon isotope ratios may be able to increase discrimination of electrical tapes, particularly with regards to different rolls of tape of the same product, we assessed the δ(13)C values of backings from 87 rolls of PVC-based black electrical tape (~20 brands, >60 products) Prior to analysis, adhesives were removed to prevent contamination by adhering debris, and plasticizers were extracted because of concern over their potential mobility. This result is consistent with each of these tapes having approximately the same plasticizer δ(13)C value and proportion of carbon in these plasticizers. The δ(13)C values of the 87 PVC tape backings ranged between -23.5 and -41.3 (‰, V-PDB), with negligible carbon isotopic variation within single rolls of tape, yet large variations among tape brands and tape products. Within this tape population, carbon isotope ratios permitted an average exclusion power of 93.7%, using a window of +/-0.3‰; the combination of carbon isotope ratio measurement with additional chemical and physical analyses raises the discrimination power to over 98.9%, with only 41 out of a possible 3741 pairs of tape samples being indistinguishable. There was a linear relationship between the δ(13)C value of tape backings and the change in δ(13)C value with the extraction of plasticizers. Analyses of pre- and post-blast tape sample pairs show that carbon isotope signatures are within 0.3‰ of pre-blast values, indicating that carbon isotope values are largely preserved during an explosion.     

Adhesive tape analysis: establishing the evidential value of specific techniques

This study investigated the evidential value of specific methods of analysis for packaging tapes and clear adhesive tapes available in Australia. Fifty-eight adhesive tapes were analyzed using a wide range of optical, physical, and chemical techniques. The results were collated for the purpose of creating an Australian database of adhesive tapes, which would be of assistance in criminal investigation. Each technique was evaluated for its discriminating power, both for comparative purposes and for the identification of adhesive tapes by comparing unknown samples with the database. The combined discriminating power of the techniques applied is very high. It is possible to individually identify the source of an unknown adhesive tape sample in many instances by searching the database. It is also possible to form an opinion on the significance of a failure-to-discriminate result in comparative casework. Further work is still needed to expand and update the database, as well as compiling data on the relative market share of various products.     

Characterization of Blue Pigments Used in Automotive Paints by Raman Spectroscopy

Micro‐Raman spectroscopy was applied to forensic identification of pigments in paint chips and provided differentiation between paint samples. Sixty‐six blue automotive paint samples, 26 solid and 40 metallic were examined. It was found that the majority of the collected Raman spectra provided information about the pigments present. However, in some cases, fluorescence precluded pigment identification. Using laser excitation at longer wavelengths or pretreatment to effect photobleaching often resulted in reduced fluorescence, particularly for solid color samples, and allowed pigment identification. The examined samples were compared pairwise taking into account number, location, and intensity of absorption bands in their infrared spectra. The estimated discrimination power ranged from 97% for solid paint samples to 99% for metallic paint samples.     

Identification of pressure-sensitive adhesive polypropylene tape

Identification of colorless, transparent, pressure-sensitive adhesive polypropylene tape (PP tape) was performed using infrared absorption spectrometry (IR) and pyrolysis gas chromatography mass spectrometry (Py-GC/MS) to determine the pressure-sensitive adhesive. Twenty different products of colorless, transparent PP tapes were examined in this study, and the results of analysis of IR spectra and Py-GC/MS were classified into twelve groups. In addition, the tapes were classified into 14 groups on the basis of IR measurement of release agent present in the backside. The results indicate that colorless, transparent PP tapes can be distinguished in terms of manufacturer, thereby demonstrating that this method of identifying colorless, transparent PP tape is effective. Moreover, the method was applied to the analysis of an actual forensic sample.     

Fingerprints and DNA: STR typing of DNA extracted from adhesive tape after processing for fingerprints

An exhibit that is often received for examination in cases of robbery or terrorist activity is adhesive tape. This type of exhibit can often, but not always, be successfully processed for fingerprints. The question arises whether or not it is possible to extract and type DNA after the tape has been sequentially processed for fingerprints. In this work, various donors left fingerprints on the adhesive side of tapes. The tapes were then sequentially processed for fingerprints using an alternate light source, cyanoacrylate fuming, and staining with BY-40 and then crystal violet. DNA was subsequently successfully extracted, amplified and typed for six STR loci.     

A validation study for duct tape end matches

Fracture matches are considered to be the strongest association achievable in forensic examinations of glass, metal, wood, plastic, paint, tape, and other trace evidence. Despite being fairly routine examinations, few publications exist to support their admissibility in court. This study was designed, using duct tape as the fractured medium, to determine the validity and error rate associated with conducting end match (fracture match) examinations on this material. Five test designs, which varied either the source roll of tape or manner of separation (torn or cut) from the roll, were administered to four analysts with instructions to examine the assigned test sets for end matches. If an end match was not identified by the initial analyst, the entire test set was independently evaluated by the remaining three analysts. Results indicated that while tape grade did not hinder end match identification, the manner of separation could affect results.     

The Evidentiary Significance of Automotive Paint from the Northeast: A Study of Red Paint

This population study was conducted to assess the frequency of physical, microscopical, and chemical properties of automotive paint chips. Population studies of trace evidence provide valuable analytical data for criminalists to assess evidentiary significance. Two‐hundred automotive paint chips were collected from auto body shops from the Northeastern United States. All samples were analyzed using stereomicroscopy, brightfield, and polarized light microscopy. Red paints were targeted for further analysis using a sequence of modern instrumental techniques commonly used by forensic paint examiners: Fourier‐transform infrared (FT‐IR), Raman, and ultraviolet–visible (UV–Vis) microspectroscopy. The discrimination potential of each analytical method was evaluated by inter‐comparing the paint samples. Results demonstrated that macroscopic and microscopic properties were able to differentiate 99.995% of the population (one undifferentiated pair out of 19,900). When combined with either FT‐IR or UV–Vis microspectroscopy, all paints were differentiated. The results of this research lead to the conclusion that one would not expect to encounter two indistinguishable paint chips originating from different sources during the investigation of a single event.     

A validation study for vinyl electrical tape end matches

Fracture matches are considered the strongest conclusion in the forensic examination of rigid materials, such as glass, metal, and paint. However, publications that support the fracture matching of polymeric films, such as tape backings, are limited. This study was designed to determine the validity and error rate associated with conducting end-match (fracture match) examinations on vinyl electrical tape. Test designs varied the source roll of tape, test preparer, or mode of separation from the roll. Results indicated that each affected the resulting severed tape ends. The analysts examining the end matches also had an effect on the results. Eight end matches in the study were not identified by the initial analysts and were considered inconclusive. One end match was misidentified, resulting in one false positive and an error rate of 0.049%. These results support a comprehensive physical and chemical tape comparison regardless of indications of an end match.     

Adhesive tape on the face--criminalistic aspects

Under forensic differential diagnostic aspects postmortem findings of adhesive tape in the face suggest either suicide, an autoerotic accident or homicide, in which case the adhesive tape could have been used for sealing the mouth or as a means to commit the homicide itself. 9 autopsy cases are described as examples with this constellation and discussed under criminological aspects.     

Raman identification of drug of abuse particles collected with colored and transparent tapes

Raman microscopy is a useful tool for the analysis of drug particles collected with adhesive tapes. In this work, first, the spectra of thirty drugs of abuse, degradation products, metabolites, and common cutting agent standards were recorded and the Raman bands observed were summarized providing the forensic analyst useful information for the identification of drug evidence. Then, the collection of different drug particles by a fingerprint lifting tape commonly used to remove and store fingerprints and fibers, and a white and green packaging tape, followed by the subsequent identification of the drugs by confocal Raman spectroscopy was performed. The particles were analyzed on top of the tapes, trapped between glass slides and the tapes, trapped in the tape folded over itself in the case of the transparent tape, and after folding and unfolding the tape in the case of the colored tape. The results obtained by the different approaches show that both tapes did not compromise the drugs spectra. However, the use of transparent tape is preferred because this tape allows the previous visual detection of the particles. Finally, several drug and sugar particles were spread over a clean table and inside a pocket, and the particles were collected with transparent tape and then properly identified. Although good results were obtained in both cases, the amount of fibers and other substances present in the collection area made the previous detection of the particles difficult and increases the analysis time.     

Recovery of Trace DNA on Clothing: A Comparison of Mini‐tape Lifting and Three Other Forensic Evidence Collection Techniques

Trace DNA is often found in forensic science investigations. Experience has shown that it is difficult to retrieve a DNA profile when trace DNA is collected from clothing. The aim of this study was to compare four different DNA collection techniques on six different types of clothing in order to determine the best trace DNA recovery method. The classical stain recovery technique using a wet cotton swab was tested against dry swabbing, scraping and a new method, referred to as the mini‐tape lifting technique. Physical contact was simulated with three different “perpetrators” on 18 machine‐washed garments. DNA was collected with the four different DNA recovery methods and subjected to standard PCR‐based DNA profiling. The comparison of STR results showed best results for the mini‐tape lifting and scraping methods independent of the type of clothing. The new mini‐tape lifting technique proved to be an easy and reliable DNA collection method for textiles.     

Unusual suicidal smothering by means of multiple loops of adhesive gummed tape

In suicidal asphyxia smothering is very rare, especially when caused by winding strips of adhesive tape around the head to cover the nose and mouth. The authors report a very unusual case in which the deceased, a 66-year-old man, was found with two strips of tape wound around his head: the first, more superficial tape was wrapped six times and the second was wrapped nine times. Only integration of the crime scene data with those of the autopsy and the patient's psychological profile enabled identification of the event as suicide.     

Firearms discharge residue sample collection techniques.

Critical comparisons of Ba and Sb in firearms discharge residue were made on samples collected by three independent collection technqiues. Collection materials studied were transparent adhesive tape, (Scotch Brand), a solution of cellulose acetate in acetone ("Film Lift"), and plastic-shafted cotton swabs wetted with dilute nitric acid. Flameless atomic absorption analyses were performed with a Jarrell-Ash Model 810 instrument equipped with a tantalum strip atomizer. Tape and cotton swabs gave comparable positive indications of residue, with frequencies of 90 and 80%, respectively. The plastic Film Lift gave fewer positives, with a frequency of 50%. With the transparent tape lift, gunshot residue particles are discernible, making nondestructive microscopic identification possible prior to destructive elemental analysis.     

The random presence of glass and paint on the clothing and footwear of members of the general population: A US baseline survey at various seasons

This study assists the interpretation of glass and paint evidence by filling an existing gap in the background occurrence that reflects the socioeconomic and demographic circumstances in the United States. The collection was performed in a college US city (Morgantown, West Virginia) to determine the effect of the type of clothing worn at different seasons on the presence of glass and paint. Tape lifts and sole scrapings (1038) were collected from 210 participants and up to six clothing and footwear areas per individual. Glass fragments were analyzed via polarized light microscopy (PLM), refractive index (RI), micro-X-Ray fluorescence (μXRF), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), while paint specimens were examined by light microscopy and infrared spectroscopy (μFTIR). Higher occurrences of glass and paint were found in the winter season. The winter collection yielded 10 glass fragments and 68 paint particles, whereas the summer collection resulted in one glass fragment and 23 paint particles. The percentage of individuals with traces varied between seasons; 7% of individuals in the winter and 0.9% in the summer had glass, whereas 36% of individuals in the winter and 19% in the summer bore paint. Lastly, when considering the overall garment and footwear areas, glass was detected in 1.4% of the winter set, compared to 0.2% in the summer collection; paint was found in 9.2% of the winter collection, whereas only 4.2% was found in the summer set. There were no instances where both glass and paint were detected on the clothing and footwear of the same individual.