碘热升华喷枪显现潜手印的应用研究

本文提出一种以石英灯为加热器的碘热升华喷枪显现潜手印的新方法。实验表明,该技术方法操作简便,适用范围广,手印显出率高,尤其是显现遗留在墙面、本色铝合金表面、UPVC表面的潜手印效果明显。     

33.15及33.6探针对中国人DNA指纹图的研究

目的统计用33．15及33．6探针对中国人进行DNA指纹图检验的群体调查资料，为实际案件的检验提供理论依据。方法应用33．15及33．6探针为中国北京地区无关群体的血液进行DNA指纹图分析。结果应用33．15探针检验15人的DNA指纹图，无关个体间相关机率为1．03×10-15，两无关个体间出现同一谱带的平均概率0．176；应用33．6探针检验19人的DNA指纹图，无关个体间相关机率为1．53×11-11，两无关个体间出现同一港带的平均概率为0．187；两探针均符合孟德尔遗传规律，均具有组织同一性。结论本研究结果可应用于法医物证检验的亲子鉴定及个体识别。     

同源激光雕刻橡塑印章印文的鉴别方法

目的找出同源激光雕刻橡塑印章印文之间的特征差异,建立检验鉴定此类印章印文的鉴别方法。方法制作14枚同源激光雕刻橡塑印章,借助文件仪、显微数字分析仪等仪器观察分析其盖印的印文样本。结果找出了各种细节特征差异。结论同源性激光雕刻橡塑印章因其规格性特征符合很好,检验鉴定要以细节特征比对为主。     

The recovery of finger marks from soot-covered glass fire debris.

This study aimed to expand the scope of previous research by assessing the effectiveness of soot-removal techniques on glass from petrol-bomb debris using methods of 1% and 2% sodium hydroxide (NaOH) solutions, ultrasonic bath and vacuum suction. Of particular interest were the 1% and 2% NaOH solutions applied to the soot-covered surfaces. Petrol bombs containing petrol or a 50:50 mix of petrol and motor oil were exploded and the debris was collected for analysis. Favourable results were found to varying degrees using each of the soot-removal methods with the 1% and 2% NaOH wash solutions, being the most useful. The 2% NaOH solution also proved successful as a soak to loosen and remove heavy contamination of soot and accelerants without damaging the finger mark beneath. This study also found that recovery of finger marks in blood from beneath soot using the 2% NaOH solution was possible. Finger marks were also applied to glass bottles with plastic adhesive labels, and providing the fire damage is not too great marks were also retrievable. Results from this study lead to the conclusion that the NaOH wash solution is ideally suited for soot removal to reveal latent and blood-contaminated marks both within the laboratory and at crime scenes.     

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.     

Shoe print examinations: effects of expectation, complexity and experience

Even though trace evidence is becoming more and more important in legal cases, only little is known about the influence of task and context factors on comparative judgments. In the present study we investigated how expectations and complexity affect shoe print examinations and to what extent differences exist between beginners and experienced examiners. Twelve examiners assessed similarity between a shoe print and a shoe for eight different cases. For half the cases expectation was induced by providing additional incriminating evidence. A complex case meant that the print was relatively noisy, for example because the perpetrator rotated his foot. A simple case meant that the print was clear. The results showed that there was no effect of expectation and no effect of experience. Only complexity affected the examiners' assessments: when the background was noisy, the acquired features received a lower evidential value than when the background was clear. Apparently, examiners compensated for the quality of the print and were more cautious in drawing conclusions when prints were less clear. Even though the results allow for some optimism with regard to the influence of expectations on shoe print examinations, it has to be taken into account that the Dutch procedure is supported by a formal guideline, which may (partly) explain the present findings.     

A methodology for finger mark research

Currently there is no standard way of carrying out research into finger mark enhancement techniques. Individuals, groups or establishments tend to use different methodologies depending on a number of factors, especially finance and time. However, data published in the literature can be misleading to the forensic community if the data generated reflects research involving very few finger marks or if those finger marks have been deliberately doped with an unnatural balance of sweat or an unusual contaminant. This paper presents an experimental methodology which is intended to establish minimum standards for those carrying out finger mark enhancement research (at least within the United Kingdom) and bring some consistency to the process. It will aim to identify the many variables encountered when dealing with finger marks and suggest experimental methods to take these into account. It will also present the key stages of the progression of a process from a laboratory concept to a tool used on operational work.     

Semen analysis using methods of molecular genetics--a case report

The presented case report describes the exclusion of the suspect of a sexual offence by means of methods of molecular genetics. Pretests for prostate-specific antigen performed at the beginning of the investigation and cytological sperm tests were negative. Nevertheless, by combining the methods of differential lysis and DNA quantification a small number of spermatozoa could be demonstrated in the trace evidence. Subsequently, the profile of the woman's boyfriend, with whom she had had unprotected vaginal intercourse two days before the incident, could be detected in the fraction of the hard lysis.     

Estimating actual foot size from a static bare foot print in a White British Population

In forensic intelligence-gathering it would be useful to be able to estimate the size of a perpetrator's foot from a standing bare footprint found at the scene of crime. Currently, the advice is to add a fixed amount to the length of the footprint (typically 1.5 or 2.0 cm), but there is little evidence for this approach. This study used measured footprint and actual foot lengths from 146 participants from the white British student population of a University in the UK. Data were analysed using multiple regression with foot length as the dependent (outcome) variable and footprint length and sex as the independent variable/factor respectively. Sex was not a significant predictor. The regression equation for the best estimate of the foot length is 19.89 + 0.95 × print length ± 8 mm.     

The influence of polymer type, print donor and age on the quality of fingerprints developed on plastic substrates using vacuum metal deposition.

This study investigated fingerprint development on five different polymer substrates using vacuum metal deposition (VMD). The conditions required for optimum development are shown to depend on a number of factors. No one set of conditions will result in good development in all situations. Polymer type has been confirmed as a major factor in determining the types of development that will occur and the optimum VMD conditions required. For more consistently successful VMD development, polymer type should be determined before selecting conditions. While polymer type is a key factor in determining optimum development conditions, there may be variation of the optimum conditions within a polymer type, most likely due to the presence of additives in the plastic. The heaviness of a latent print, i.e. amount of residue that constitutes the print, also affects the VMD conditions required. The donor, manner of deposition, and age of a print affect the heaviness of the deposit. The heavier the print, the higher the gold count necessary for successful VMD development. The occurrence of 'empty prints' (i.e. zinc deposition on the general background but not on or between the print ridges) was found to be related to polymer type and print heaviness. Heavy prints on PVC and PET are the most likely to be 'empty' after VMD treatment. The development of empty prints may be due to the diffusion of print residue into the print valleys. Pre-treatment with cyanoacrylate fuming was also found to affect VMD development. In particular, it was shown that cyanoacrylate pre-treatment was beneficial for print development on PET and PVC. The results of this study were used to formulate guidelines for use as an aid by laboratories using VMD in casework.     

Identification of Prostate-Specific Antigen and Spermatozoa from a Mixture of Semen and Simulated Gastric Juice

Abstract:  The detection of prostate-specific antigen (PSA) and visualization of spermatozoa from forensic-type samples containing semen exposed to simulated gastric juice was investigated as a support for forensic practice. Samples of simulated gastric juice mixed with semen were prepared and incubated for up to 4 h at 37°C. Samples were deposited on cotton cloth and on ceramic plates and allowed to dry. The samples were examined for the presence of PSA using the Seratec^® PSA Semiquant immunochromatographic membrane test. Microscope slides were prepared, stained, and analyzed for spermatozoa. Spermatozoa were detected in all samples, and PSA was detected on neat samples and on samples from the ceramic plate after incubation for up to 4 h. PSA was not detected in the samples deposited on cotton cloth at incubation times greater than 15 min. This may serve as a support for examinations performed when vomit or vomit-stained evidence is submitted for analysis.     

Development of a finger printing device for use on a mobile robot

In this paper, we describe the development of a device for fuming fingerprints with cyanoacrylate (Super Glue) to enable police tactical units to obtain fingerprint evidence from suspicious packages using a remote-controlled robot. Through a series of initial experiments and preliminary designs, we show that effective cyanoacylate fuming requires sufficient heat, humidity, and airflow. This work led to the development of a final working prototype, called robot accessory for fuming fingerprint evidence (RAFFE), which is currently being field tested by the Calgary Police Service.     

The effects of latent print processing on questioned documents produced by office machine systems utilizing inkjet technology and toner

Counterfeiting of currency and identity documents, death threats, illegitimate business transactions, and terrorist-related activities are some examples of the types of crimes that often involve documents produced from printers and copiers. Although standard protocol typically requires a questioned document (QD) examination prior to latent print (LP) processing, occasionally, items of evidence may be submitted for a QD examination following the application of a series chemicals utilized in the development of latent fingerprints. In such cases, the forensic examiner must take into account any previous treatments prior to initiating an examination on documents produced with a printer or copier. This study was devised to examine the effects of a latent print development technique [ninhydrin, physical developer, and a bleach enhancer] on the physical and chemical examination of documents produced from copiers and printers.     

根据手指节皱纹推断年龄的研究及应用

为了快速、准确、简便地推断年龄,笔者收集广西区1195人活体手指背照片.通过对中指背近节横纹特征的观察,并用解剖学、法医学、数理统计学的理论进行研究,结果发现手指背横条纹随着年龄的增长呈规律变化,即皱纹由少到多、由浅到深、由不明显到明显、粗纹间距由窄变宽的规律特征,具有一定的法医学应用价值.     

Index and ring finger ratio--a new sex determinant in south Indian population

Identification of human remains is an imperative element of any medicolegal investigation, and a challenging task for forensic experts and physical anthropologists worldwide. Three hundred adult hands (150 males and 150 females) belonging to south Indian population were studied to investigate sexual dimorphism of the index and ring finger ratio. The index and ring finger ratio is derived by dividing the index finger length by ring finger length. The index and ring finger ratio is found to be higher in females. Index and ring finger ratio < or =0.9700 identified 80% of males for both hands, and ratio >0.9700 identified 74% females for the right hand and 78% for the left hand accurately. This study may prove useful to determine the sex of an isolated hand when it is subjected for medicolegal examination.     

Application of fluorescence lifetime imaging (FLIM) in latent finger mark detection

Fluorescence lifetime imaging (FLIM) in frequency domain enables the mapping of the spatial distribution of fluorescence lifetimes of a specimen. It has been extensively applied in biology. In this paper, a theoretical analysis for the fluorescence lifetime determination of latent finger mark samples is described, which is followed by the feasibility study of using FLIM in frequency domain for latent finger marks detection. Preliminary experiments are carried out with latent finger marks treated with a fluorescent powder on two different substrates. The resulting fluorescence lifetime image of finger mark revealed a good contrast, and was able to detect the latent finger marks clearly.     

Application of fluorescence lifetime imaging (FLIM) in latent finger mark detection

Fluorescence lifetime imaging (FLIM) in frequency domain enables the mapping of the spatial distribution of fluorescence lifetimes of a specimen. It has been extensively applied in biology. In this paper, a theoretical analysis for the fluorescence lifetime determination of latent finger mark samples is described, which is followed by the feasibility study of using FLIM in frequency domain for latent finger marks detection. Preliminary experiments are carried out with latent finger marks treated with a fluorescent powder on two different substrates. The resulting fluorescence lifetime image of finger mark revealed a good contrast, and was able to detect the latent finger marks clearly.