Gamma Irradiation as a Biological Decontaminant and Its Effect on Common Fingermark Detection Techniques and DNA Profiling

Abstract:  The use of disease-causing organisms and their toxins against the civilian population has defined bioterrorism and opened forensic science up to the challenges of processing contaminated evidence. This study sought to determine the use of gamma irradiation as an effective biological decontaminant and its effect on the recovery of latent fingermarks from both porous and nonporous items. Test items were contaminated with viable spores marked with latent prints and then decontaminated using a cobalt 60 gamma irradiator. Fingermark detection was the focus with standard methods including 1,2-indanedione, ninhydrin, diazafluoren-9-one, and physical developer used during this study. DNA recovery using 20% Chelex extraction and quantitative real-time polymerase chain reaction was also explored. Gamma irradiation proved effective as a bacterial decontaminant with D -values ranging from 458 to 500 Gy for nonporous items and 797–808 Gy for porous ones. The results demonstrated the successful recovery of latent marks and DNA establishing gamma irradiation as a viable decontamination option.     

The effect of electron beam irradiation on forensic evidence. 1. Latent print recovery on porous and non-porous surfaces

The recent use of the postal system as a means of delivering anthrax spores via several contaminated envelopes has led to the selective irradiation of mail. These as yet unsolved attacks and the U.S. Postal Service's decision to irradiate certain types of mail has led to some unexpected complications. The high doses of radiation required to destroy biological agents like anthrax are sufficient to induce damage to other materials present in the envelope. There have been reports of damage to many different items that have been subjected to irradiation, including paper, precious gems, plastic, computer discs, and electronics. However, few studies have examined the effect of such treatments on items of forensic interest. In this paper, the authors focused on the impact of the irradiation process on the ability to visualize latent prints. This experiment involved using several donors, substrates (both porous and non-porous), and visualization reagents. The results indicate that the irradiation process can have a detrimental effect on the success of certain visualization reagents.     

The Development and Evaluation of Radiological Decontamination Procedures for Documents,Document Inks,and Latent Fingermarks on Porous Surfaces*†

Abstract: Criminal acts such as an attack utilizing a radiological dispersal device (RDD or dirty bomb), the manufacture of such a device, or the illicit trafficking of radioactive materials would warrant a criminal investigation. This could involve the collection, transportation, and analysis of radiologically contaminated trace evidence. But are law enforcement agencies and forensic scientists capable of dealing with this? This research investigates the decontamination efficacy of two decontamination techniques (chemical and physical) designed for the removal of radiological material from documents of forensic importance. The impact that these procedures have on the development of latent fingermarks and the forensic analysis of the inks on these documents is also studied. It was found that slight changes in the color and chemical composition of a variety of document inks and a destruction of fingermark ridges occurred after chemical decontamination. Physical decontamination had no impact on these parameters.     

Effects of CBRN Decontaminants in Common use by First Responders on the Recovery of Latent Fingerprints—Assessment of the Loss of Ridge Detail on Glass

Following a CBRN incident, first responders use decontamination procedures to reduce the risk of exposure. The effect of decontamination on forensic trace material has, however, not been fully examined. This study sought to evaluate the effect of five different physical or chemical decontamination materials on the recovery of latent fingerprints. Fingerprints were deposited on glass slides, decontaminated, and assessed on the presence of ridge detail. The results demonstrate that decontamination affects the quality of latent fingerprints substantially. On at least 61% of the fingerprints, a reduced amount of ridge detail was observed upon decontamination. Furthermore, development with cyanoacrylate appeared not to succeed anymore. Instead, the ability of vacuum metal deposition to successfully develop decontaminated fingerprints is demonstrated. The results from this study may contribute to an increased forensic awareness regarding decontamination and emphasize the necessity for further research into new item decontamination procedures or new forensic initiatives prior to decontamination.     

Comparison of quantitative PCR and culture-based methods for evaluating dispersal of Bacillus thuringiensis endospores at a bioterrorism hoax crime scene

Since the anthrax mail attacks of 2001, law enforcement agencies have processed thousands of suspicious mail incidents globally, many of which are hoax bioterrorism threats. Bio-insecticide preparations containing Bacillus thuringiensis (Bt) spores have been involved in several such threats in Australia, leading to the requirement for rapid and sensitive detection techniques for this organism, a close relative of Bacillus anthracis. Here we describe the development of a quantitative PCR (qPCR) method for the detection of Bt crystal toxin gene cry1, and evaluation of the method's effectiveness during a hoax bioterrorism event in 2009. When combined with moist wipe sampling, the cry1 qPCR was a rapid, reliable, and sensitive diagnostic tool for detecting and quantifying Bt contamination, and mapping endospore dispersal within a mail sorting facility. Results from the cry1 qPCR were validated by viable counts of the same samples on Bacillus-selective agar (PEMBA), which revealed a similar pattern of contamination. Extensive and persistent contamination of the facility was detected, both within the affected mailroom, and extending into office areas up to 30m distant from the source event, emphasising the need for improved containment procedures for suspicious mail items, both during and post-event. The cry1 qPCR enables detection of both viable and non-viable Bt spores and cells, which is important for historical crime scenes or scenes subjected to decontamination. This work provides a new rapid method to add to the forensics toolbox for crime scenes suspected to be contaminated with biological agents.     

Recovery efficiencies of anthrax spores and ricin from nonporous or nonabsorbent and porous or absorbent surfaces by a variety of sampling methods*

The 2001 anthrax letter cases brought into focus the need to establish the most effective environmental sampling procedures. Results are presented from two studies aimed at establishing the best procedures for everyday surfaces likely to be contaminated after the release of environmentally stable bioaggressive agents, as exemplified by anthrax spores and ricin. With anthrax spores, contact plates, with mean retrieval rates of 28-54%, performed better than other methods by a wide margin for flat nonporous, nonabsorbent surfaces. They also proved best on flat porous, absorbent materials, although recoveries were low (<7%). For both agents, dry devices (swabs, wipes, Trace Evidence Collection Filters) had universally poor retrieval efficiencies with no significant differences between them. Among moistened devices (wipes, swabs, and Sample Collection and Recovery Devices), wipes were generally best, albeit with considerable cross-over among individual readings (highest mean recoveries for anthrax spores and ricin 5.5% and 2.5%, respectively, off plastic).     

To destroy snail mail: Is this the sole solution for anthrax contaminated letters?

Suspicious packages, strange addresses on envelopes and/or the presence of particular powders: these are the most popular aspects of letters containing Bacillus anthracis. Since the World Trade Center tragedy, alarmism about chemical or biological attacks is always in force. The Italian Ministry of Foreign Affairs introduced new procedures to be followed in case suspected anthrax letters are identified (Ministry of Health PROT. 400.3/120.33/4786 of 23/10/2001). Scientists have to collect samples from surfaces and infectious waste have to be placed in autoclavable bags for decontamination. After the sterilization, mails and packages are burnt thus eliminating every biological trace present on their surface. As a matter of fact, after sterilization, DNA is still present and can be analyzed for forensic purposes: for this reason, here we report on the importance of preserving sterilized substrates. We recreated false infected mails with biological traces on their surfaces, sterilized them and, subsequently, we took samples of biological stains and processed them for DNA quantification and typing. We recreate different time conditions consistent with those of the postal service too. Real-Time PCR and DNA typing showed that, even if sterilization destroys the bacillus, human genomic traces still persist and we obtained both complete and partial profiles of samples’ donors. To conclude, the problem of anthrax contaminated letter call for peculiar and standardized procedures; nonetheless, we show that burning evidences after the sterilization process does not appear to be the best solution since there is a loss of biological material which could be decisive for forensic purposes.     

Effect of Sterilants on Amplification and Detection of Target DNA from Bacillus cereus Spores

To conceal criminal activity of a bioterrorist or agroterrorist, the site of pathogen generation is often treated with sterilants to kill the organisms and remove evidence. As dead organisms cannot be analyzed by culture, this study examined whether DNA from sterilant‐treated Bacillus cereus spores was viable for amplification. The spores were exposed to five common sterilants: bleach, Sterilox®, oxidizer foam (L‐Gel), a peroxyacid (Actril®), and formaldehyde vapor. The spores were inoculated on typical surfaces found in offices and laboratories to test for environmental effects. It was found that the surface influenced the efficiency of recovery of the organisms. The DNA isolated from the recovered spores was successfully detected using RT‐qPCR for all treatments except for formaldehyde, by amplifying the phosphatidylinositol phospholipase C and sphingomyelinase genes. The results demonstrated that evidence from sites treated with sterilants can still provide information on the uncultured organism, using DNA amplification.     

Decontamination procedures for drugs of abuse in hair: are they sufficient?

This paper reviews the methods for decontaminating hair exposed to external solutions of drugs of abuse. Exposure of hair to cocaine at 1 μg/ml for 5 min is sufficient to contaminate hair, yet decontamination is a very slow process. Using externally contaminated hair, a number of decontamination procedures were attempted, and none removed all the contamination. The percentage of external contamination removed depended on the hair type, with thick black hair being the most resistant to decontamination. Hair treated by dying incorporated externally applied drugs differently, depending on the hair type. Thick black hair became more absorbent whereas thin brown hair became less absorbent. Kinetic wash criteria are evaluated for their ability/inability to determine if hair has been contaminated from external sources. A theoretical framework for the incorporation and removal of drugs from hair is discussed, and the hypothesis that inaccessible domains exist in hair which trap drugs is critically examined. The results presented in this paper strongly suggest that much more information on the decontamination of hair and the differentiation of exogenously and endogenously incorporated drugs is needed before hair analysis can be employed in most forensic applications. We propose that the radioactive tracer methods discussed herein are well suited for evaluating any new decontamination or extraction technique.     

An Update on the Hazards and Risks of Forensic Anthropology,Part II: Field and Laboratory Considerations

This paper focuses on potential hazards and risks to forensic anthropologists while working in the field and laboratory in North America. Much has changed since Galloway and Snodgrass published their seminal article addressing these issues. The increased number of forensic practitioners combined with new information about potential hazards calls for an updated review of these pathogens and chemicals. Discussion of pathogen hazards (Brucella, Borrelia burgdorferi, Yersinia pestis, Clostridium tetani and West Nile virus) includes important history, exposure routes, environmental survivability, early symptoms, treatments with corresponding morbidity and mortality rates, and decontamination measures. Additionally, data pertaining to the use of formaldehyde in the laboratory environment have resulted in updated safety regulations, and these are highlighted. These data should inform field and laboratory protocols. The hazards of working directly with human remains are discussed in a companion article, “An Update on the Hazards and Risks of Forensic Anthropology, Part I: Human Remains.”     

A novel approach to obtaining reliable PCR results from luminol treated bloodstains

In recent years the forensic scientist has been afforded great advances in technology both in the detection of latent bloodstains and in acquiring reliable DNA typing results from very small pieces of physical evidence. Scientists are now able to detect minute quantities of latent bloodstains by utilizing the luminol reagent, oftentimes indicating that an attempt has been made to conceal any evidence of bloodshed. With the introduction of PCR based technology to the forensic arena, scientists are now routinely able to obtain DNA typing results from previously insufficient amounts of biological material, items as small as a single hair, saliva on a cigarette butt, or a bloodstain the size of a pin head. We present here a merging of these two advances coupled with a new collection medium for post luminol treated latent bloodstains. The forensic scientist is now able to routinely isolate and recover an adequate amount of DNA suitable for PCR typing at all of the Promega GenePrint PowerPlex 1.1 loci. In this study, several dilutions of latent bloodstains were prepared in an effort to simulate transferred bloodstains that are routinely encountered in a crime scene setting. The latent bloodstains were treated with luminol and subsequently collected using conventional cotton tipped swabs as well as a Puritan sponge tipped swab. PCR typing at the Promega GenePrint PowerPlex 1.1 loci was then attempted upon all dilutions of the latent bloodstains for both collection mediums. The results clearly indicate that it is now routinely possible to recover adequate amounts of DNA suitable for PCR typing upon post luminol treated bloodstains.     

Morphometry of latent palmprints as a function of time

In many crimes, the elapsed time between production and collecting fingermark traces is crucial. and a method able to detect the aging of latent prints would represent an improvement in forensic procedures. Considering that as the latent print gets older, substantial changes in the relative proportion of individual components secreted by skin glands could affect the morphology of ridges, morphometry could be a potential tool to assess the aging of latent fingermarks. Then, considering the very limited research in the field, the present work aims to evaluate the morphometry of latent palmprint ridges, as a function of time, in order to identify an aging pattern. The latent marks were deposited by 20 donors on glass microscope slides considering pressure and contact angle, and then were maintained under controlled environmental conditions. The morphometric study was conducted on marks developed with magnetic powder in 7 different time intervals after deposition (0, 5, 10, 15, 20, 25 or 30 days); 60 ridges were evaluated for each developed mark. The results showed that: 1) the method for the replacement and mixing of skin secretions on the palm was appropriate to ensure reproducibility of latent prints, and 2) considering the studied group, there was a time-dependent reduction in the width of ridges and on the percentage of visible ridges over 30 days. Results suggest the possibility of using the morphometric method to determine an aging profile of latent palmprints on glass surface, aiming for forensic purposes.     

荧光钙血迹蓝钠试剂增强潜在多介质混合鞋印的应用

目的研究荧光钙血迹蓝钠试剂增强潜在灰尘水渍混合鞋印、灰尘尿渍混合鞋印、灰尘血渍混合鞋印的普适性。方法采用高压微雾雾化法,雾化增强常见的8种地板上的20%w/w灰尘含量的灰尘水渍、灰尘尿渍和灰尘血渍混合鞋印,并与平面扫描提取技术相比较。结果增强后的鞋印花纹清晰,呈亮蓝色,提取效果明显优于自然光下拍照提取,略优于平面扫描提取技术。结论荧光钙血迹蓝钠试剂能够有效增强潜在多介质混合鞋印,是一种便捷高效的潜在混合鞋印增强提取方法。     

Forensic applications of infrared imaging for the detection and recording of latent evidence

We report on a simple method to record infrared (IR) reflected images in a forensic science context. Light sources using ultraviolet light have been used previously in the detection of latent prints, but the use of infrared light has been subjected to less investigation. IR light sources were used to search for latent evidence and the images were captured by either video or using a digital camera with a CCD array sensitive to IR wavelength. Bloodstains invisible to the eye, inks, tire prints, gunshot residue, and charred document on dark background are selected as typical matters that may be identified during a forensic investigation. All the evidence types could be detected and identified using a range of photographic techniques. In this study, a one in eight times dilution of blood could be detected on 10 different samples of black cloth. When using 81 black writing inks, the observation rates were 95%, 88% and 42% for permanent markers, fountain pens and ball-point pens, respectively, on the three kinds of dark cloth. The black particles of gunshot residue scattering around the entrance hole under IR light were still observed at a distance of 60 cm from three different shooting ranges. A requirement of IR reflectivity is that there is a contrast between the latent evidence and the background. In the absence of this contrast no latent image will be detected, which is similar to all light sources. The use of a video camera allows the recording of images either at a scene or in the laboratory. This report highlights and demonstrates the robustness of IR to detect and record the presence of latent evidence.     

炭疽信件的物证检验

作者对炭疽信件恐怖袭击有关物证鉴定问题进行了探讨,包括炭疽信件上的微生物物证检验和传统物证检验,污染的消除和人员防护等重要问题.     

Determination of drugs of abuse in hair: evaluation of external heroin contamination and risk of false positives

One of the most controversial point regarding the validity of hair testing is the risk of false positive due to external contamination. The aim of our experience is to verify if a 5 consecutive days contamination with a small amount of a powdered mixture of heroin hydrochloride and acetylcodeine hydrochloride (10:1 w/w) will last sufficiently long to make a contaminated subject indistinguishable from active users, and if normal washing practices together with the decontamination procedure are sufficient to completely remove the external contamination.Our results suggest that decontamination procedures are not sufficient to remove drugs penetrated into hair from external source. In fact, all contaminated subjects were positive for opiates (heroin, 6-MAM, morphine, acetylcodeine and codeine) for at least 3 months.Significant 6-MAM concentrations (>0.5 ng/mg) were found in each subject until 6th week. Further, 6-MAM/morphine ratio were always above 1.3.     

茚三酮固体介质法显现不同纸张表面潜指纹

茚三酮是显现渗透性客体上潜在汗液手印的最常用方法之一,采用微量物证提取纸和茚三酮溶液有机结合制作的茚三酮固体介质可以有效避免客体表面背景着色,不容易引起纸张油墨扩散,另外避免使用的溶剂易燃。能够更便捷的显现现场指纹,并且能够突破茚三酮只能显现渗透性客体的局限,拓宽茚三酮显现客体的范围,在热敏纸上潜指纹的显现方面有独特的应用优势。     

孢粉学在法医学中的应用

孢粉学是研究植物孢子和花粉(简称孢粉)的科学,是一门新兴的边缘学科。由于孢粉具有个体小、质量轻、数量多,不容易被发现等特征,给法医工作者留下证据,为破案提供有利线索,因此孢粉学在法医学实践应用中具有良好的应用前景。此文通过阐述孢粉学的概况、分类、形态特征及传播的规律,分析孢粉学在法医学上应用的优点和局限性,旨在为进一步完善孢粉学在法医学中的应用提供参考。     

Some Examples of Applications of a Microthermal Desorption Device in the Forensic Laboratory

Abstract:  Several applications of a microthermal desorption device for analysis of small forensic samples are presented. The method uses a solid phase microextraction holder with the fiber removed. In addition to samples of inks on paper, this device was successfully used for analysis of toners, various stains on bank notes, and lipstick stains on paper. Other small items encountered in a forensic science laboratory were also analyzed: particles of smokeless powder, particles of coffee, and automotive clear topcoat layer. The desorbed compounds were analyzed by gas chromatography with a flame ionization detector or by gas chromatography–mass spectrometry. This device can be used in connection with any kind of gas chromatograph. By selection of different injector temperatures, fractionated thermal desorption of samples is achieved. The procedure was demonstrated on samples of ballpoint pen ink of various age.     

Release of tissue paraquat into formalin solution during fixation

Formalin-fixed tissues and formalin solutions are among the most frequently found materials in pathology and forensic science laboratories. However, these materials are seldom used for the identification of poisons for forensic toxicology purposes. In this study, the possibility that paraquat may be released from formalin-fixed tissues during the fixation process was investigated. However, because of the interference of formaldehyde on the reduction of paraquat with dithionite reagent, paraquat in formalin solutions was treated with ion-pair column chromatography and then determined by measuring the derivative spectrum of reduced paraquat. The results show that the interference of formalin on paraquat determination has been eliminated by the proposed method. Furthermore, a study on the formalin solutions of fixed organs in cases with suspected paraquat intoxication revealed that portions of tissue paraquat had been released into formalin during the fixation process. Moreover, the paraquat levels in formalin increased with increased storage time. Therefore, these data suggest that the combined concentrations of paraquat in the formalin-fixed tissues and formalin solutions might reflect more reliably the total paraquat in the postmortem tissues. This investigation could be of value to the forensic toxicologist, especially in cases in which no fresh tissue samples are available for analysis.