An investigation on the secondary transfer of organic gunshot residues

Gunshot residues (GSR) are an important forensic trace in firearm-related events. Currently, routine GSR analyses focus on the detection and characterisation of the inorganic components (IGSR). The increasing prevalence of heavy metal-free ammunition challenges these current protocols and there is an increasing interest in how the organic components of GSR (OGSR) can provide complementary information. Similar to the situation with IGSR, OGSR compounds originally deposited on the shooter during the firing process may further be transferred onto another individual or surface. Hence, the aim of this study was to provide additional information regarding the risk of a secondary transfer of OGSR. Two scenarios were investigated, the first one related to the arrest process and the possibilities of a secondary transfer arising between a shooter onto a non-shooter (e.g. between a police officer and a person of interest (POI)). The second scenario concerned the transfer of OGSR onto the non-shooter after handling a firearm for few minutes without discharging it. One calibre was chosen, the .40 S&W calibre, used by several Australian State police forces. A secondary transfer was observed in all cases for the two scenarios investigated, for three compounds of interest: ethylcentralite (EC), diphenylamine (DPA), N-nitrosodiphenylamine (N-nDPA). The firearm handling scenario resulted in a larger secondary transfer to that of the arrest scenario. Overall, the amounts of OGSR detected on the non-shooter were generally lower than that detected on the shooter and controls after the arrest scenario. The results of this study provide complementary knowledge about OGSR, which can be further used to improve the current practice and the interpretation of OGSR evidence. In particular, it highlights that the secondary transfer proposition must be considered during the interpretation of forensic findings, especially when small amounts of OGSR target compounds are detected.     

Secondary transfer of organic gunshot residues: Empirical data to assist the evaluation of three scenarios

The present study aimed at providing data to assess the secondary transfer of organic gunshot residues (OGSR). Three scenarios were evaluated in controlled conditions, namely displacing a firearm from point A to point B, a simple handshake and an arrest involving handcuffing on the ground. Specimens were collected from the firearm, the hands of the shooter and the non-shooter undergoing the secondary transfer in order to compare the amounts detected.Secondary transfer was observed for the three scenarios, but to a different extent. It was found that displacing a firearm resulted in secondary transfer in <50% of the experiments. The firearm also had an influence, as contrary to the pistol, no secondary OGSR were detected using the revolver. Shaking the hand of the shooter also transferred OGSR to the non-shooter's hand. In that case, the amount of OGSR was generally higher on the shooter than on the non-shooter. Finally, the largest secondary transfer was observed after the arrest with handcuffing with positive results in all cases using the pistol. In that scenario, the amounts on the shooter and the non-shooter were in the same range.This study highlights that the secondary transfer must be taken into account in the interpretation of OGSR. Indeed, an individual's hands might be contaminated by handling a firearm or having physical contact with a shooter.     

Automotive flock and its significance in forensic fibre examinations

The interiors of fifty eight vehicles were examined and samples were taken. All vehicles had samples of flocked material in their interiors. Flocked material was found on the window channels, window frames, door edges and in glove compartments or central console compartments. The majority of flock fibres used in the vehicles examined were carbon black pigmented polyester or nylon. A variety of dyed nylon fibres were also used in the vehicles. The discrimination power of dyed flock fibres used in the interior of vehicles was found to be 0.974. The front seats of these vehicles were examined for loose flock fibres. All vehicles had flock fibres present on the front seats. In the majority of vehicles, flock originating from material in the vehicle's interior was present on the front seats of the vehicle. The number of flock fibres present on the front seats varied greatly from car to car but did not appear to be dependant on the type of seat fabric or on which areas in the car were flocked.     

Study of injuries combining computer simulation in motorcycle-car collision accidents

This paper presents the approach of computer simulation to clarify the questions faced by forensic experts about what causes the various injuries characteristic of two motorcycle victims, including the motorcycle driver and the back seat occupant on the motorcycle, and how to exactly confirm which one of them is the motorcycle driver. Two typical motorcycle-car accident cases were reconstructed to analyze the movement and the load of both the motorcycle driver and the back seat occupant in the collision course. In case one, the back seat occupant suffered fatal head injuries when he fell on the ground after being thrown higher than the motorcycle driver over the top of the car. In case two, the compressive force loaded by the right tibia of the back seat occupant was larger and more durative compared with the motorcycle driver; the back seat occupant suffered a bursting fracture injury of his right tibia. These results might be useful for forensic experts in dealing with similar motorcycle-car collision accidents in the future.     

Discharge of a Pistol Out a Car Window with the Breech Within the Interior of the Car: Analysis of Gunshot Residue on a Car's Interior Surfaces

The defendant, the driver of the questioned car, allegedly extended his right arm over the passenger seat and fired a single shot from a 380 pistol out the passenger window with the pistol's breech within the car. A simulation of this shooting scenario using the same model car, but different year, was conducted to quantitate gunshot residue (GSR) contamination of interior surfaces within the car. The test car's dash and headliner/window frame above the pistol had the heaviest GSR contamination. The dash GSR from airborne deposition documents a firearm discharge within the vehicle. Transfer from GSR‐contaminated hands or clothing to the dash is unlikely. The heavy GSR contamination of the headliner/window frame above the pistol likely documents the window from which the pistol was fired, but additional experiments are needed to verify.     

Gasoline exposure in motor vehicle accident fatalities

Three cases are described in which deaths after motor vehicle accidents occurred as a result of positional asphyxia associated with exposure to gasoline. The deceased individuals were aged 16, 34, and 35 years, respectively (M:F = 1:2) and had all been in the back seat of motor vehicles involved in rollover accidents that had resulted in spilling of gasoline with contamination of the cabins. Major components of gasoline were detected in blood and tissues by headspace gas chromatography. Postmortem toxicologic investigations of such cases, which include analyses for volatile hydrocarbons, may therefore produce additional significant information.     

The effect of the unrestrained back seat passenger on the injuries suffered by drivers and front seat passengers in head-on collisions

In head-on collisions, loose items in the rear of the car, such as luggage or unrestrained back seat passengers can cause substantial loading on the back of the front seats. The purpose of this paper is to study if such loading increases the injury severity for the front seat occupants. Data were collected from all fatal automobile accidents for a period of 1 year in Sweden. Information was collected about the survivors as well as the decreased. Head-on collisions were selected, and the injuries of the front seat occupants were scored according to the Abbreviated Injury Scale (AIS) and the Injury Severity Score (ISS). In evaluating the injury severity, the collision energy was taken into account. The results indicate that belted front seat passengers sustain a higher injury risk with an unrestrained passenger in the back seat. These results are valid for collision speeds below 45 km/h.     

论自动驾驶汽车生产者的刑事责任

自动驾驶汽车是人类研发、制造、使用和管理的智能产品,不是犯罪主体或刑事责任主体。在自动驾驶汽车自主控制状态下发生交通事故的,其生产者、使用者和其他人员难以按照我国现有刑法的罪名定罪处罚。除非道路交通安全法和刑法有专门的规定,驾驶位人员不接管汽车或接管后无力改变交通事故结果的,不构成交通肇事罪或其他管理过失犯罪。驾驶位人员的注意义务是阻止自动驾驶汽车自主控制下发生交通事故,其注意义务不应过高。允许的风险、紧急避险理论不能为自动驾驶汽车紧急路况处理算法的生产与应用提供合法、合理的解决方案,生产者遵守算法安全标准仅可以使生产行为合法化。鉴于现行刑法不适应自动驾驶汽车应用的特性,我国应当建立以生产者全程负责为中心的新刑事责任体系,使之在自动驾驶汽车生产和应用两个阶段承担安全管理责任,生产者拒不履行自动驾驶汽车应用安全管理义务且情节严重的,应当承担刑事责任。     

A Study of the Presence of Gunshot Residue in Pittsburgh Police Stations using SEM/EDS and LC‐MS/MS

Due to possible secondary transfer of gunshot residue (GSR) onto a suspect in police custody prior to sampling, a baseline must be created for the amount of GSR present. With an increase of “lead free” ammunition, testing for both gunpowder and primer GSR is relevant. Seventy samples were collected using carbon‐coated adhesive stubs from four Pittsburgh Police Stations and vehicles to investigate these locations as sources of secondary GSR contamination. These seventy samples were analyzed for primer GSR using scanning electron microscopy‐energy‐dispersive X‐ray spectrometry. One primer GSR particle was detected; no sample was classified as positive for primer GSR. These same samples were then analyzed for gunpowder GSR using liquid chromatography coupled to tandem mass spectrometry to test for akardite II, ethylcentralite, diphenylamine, N‐nitrosodiphenylamine, 2‐nitrodiphenylamine, and 4‐nitrodiphenylamine. Ethylcentralite was quantifiable in two test samples. These results suggest there is a negligible potential for secondary transfer of primer and gunpowder GSR.     

College students’ perceptions of police use of force: do suspect race and ethnicity matter?

Incidents of police use of force continue to draw a considerable amount of attention from both researchers and the public alike. The purpose of this research is to examine the relationship between suspect race and ethnicity and perceptions of police use of force among college students. Using a vignette research design with manipulated independent variables, this study seeks to answer the question: Do suspect race and ethnicity affect college students’ perceptions of police use of force? Three vignettes were developed regarding an incident in which an encounter between a suspect and a police officer resulted in the officer using force. College students were randomly assigned to one of the three vignettes and were asked to complete a questionnaire. Results indicate that although suspect race and ethnicity do not predict perceptions of police use of force among college students, there are significant respondent race and gender effects. Male and white respondents are significantly more likely to perceive police use of force as justified compared to female and non-white respondents. The policy implications of these findings for police-citizen interactions are discussed.     

A second survey of high explosives traces in public places

This survey was carried out as a follow-up to a 1994 survey carried out by this laboratory (1) in order to determine the background levels of explosives traces in public places. The first survey concentrated on transport areas and police stations in and around London. This second study examines levels in four of the United Kingdom's major cities: Birmingham, Cardiff, Glasgow, and Manchester. Samples were taken at various transport sites and from hotels, private houses, private vehicles, and clothing. The survey showed that traces of the high explosives nitroglycerine (NG), trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), and cyclotrimethylene trinitramine (RDX) are rare within the general public environment. Only one low-level trace of RDX was detected. NG, possibly associated with the use of firearms, was detected at low levels in two samples and 2,4-DNT was detected in a separate sample. No PETN was detected in any of the samples. The results of the survey indicate that it is unlikely that persons visiting public areas could become significantly contaminated with explosives. The analytical procedures employed would also have detected ethylene glycol dinitrate (EGDN) if present at levels greater than 2 ng, nitrobenzene (NB) if present at levels greater than 50 ng, mononitrotoluenes if present at levels greater than 50 ng, and the other common isomers of dinitrotoluene if these had been present at levels in excess of 10 ng. None of these were detected. The relatively high volatility of EGDN, NB, and the mononitrotoluenes would, however, cause traces of these compounds to disperse rapidly. A proportion of the samples (approximately 7%) were analyzed for the presence of HMX. No HMX was detected.     

Race,occupational status,and pro-active police arrest for drinking and driving

The issue of pro-active police arrest bias by race, occupational status, and police patrol intensity is examined using the offense of DUI (Driving Under the Influence of alcohol). Intoxicated drivers from a 10-weekend roadside survey of vehicles randomly selected from the streets of a medium-sized southeastern metropolitan area are compared to officially arrested drivers apprehended during a corresponding time period. Upon examination, no statistically significant arrest bias was detected by the driver's race. However, compared to the roadside survey population, lower occupational status drivers (i.e., blue collar) were significantly more likely to appear in the arrested population than an upper status (i.e., white collar) driver—especially in the lightly patrolled middle and upper class residential sections of town. The significance of occupational status, when combined with the finding that race was not a significant indicator of difference between the arrested and roadside survey populations, suggests that pro-active police arrest bias is more a function of institutionally determined police patrol practices rather than overt racial prejudice on the part of individual officers.     

Police officers’ judgements of veracity,tenseness, cognitive load and attempted behavioural control in real-life police interviews

Abstract

The present experiment examined the apparently incongruent findings that police officers (i) believe that suspects show nervous behaviour when they lie but (ii) seem able to detect deceit in suspects who do not show nervous behaviours. It was hypothesized that police officers’ judgements about whether a suspect is lying would not be correlated with their judgements regarding whether the suspect is tense, but, instead, would be correlated with their judgements regarding whether suspects are having to think hard or attempting to control their behaviour.

Each of 84 police officers saw seven truths and seven lies told by suspects during their police interviews. Participants in Condition 1 were asked to indicate after each clip whether the suspect was lying, whereas participants in Condition 2 were asked to note after each clip to what extent the suspect appeared to be tense, having to think hard or attempting to control their behaviour. Condition 3 was a combination of Conditions 1 and 2 and participants were asked all the above questions. The findings support the hypotheses and therefore negate the assumption that police officers primarily look for cues of nervousness when they attempt to detect deceit.     

A study of the potential risk of gunshot residue transfer from special units of the police to arrested suspects

The presence of gunshot residues (GSRs) on arrested suspects can help the Court to form an opinion regarding the possibility of utilization of firearms by these suspects. Since the presence of a few particles can in some cases already have a strong indicative value, the GSR experts have to evaluate in their daily work the risk of a potential contamination of these suspects during their arrest. A few studies conducted on police officers and police facilities concluded that the risk of secondary transfer on arrested suspects is quite negligible. However, the case of special force units of the police should be taken into account, since these units can be assumed to be highly contaminated by GSR due to their intensive training. The aim of this study is to evaluate this possibility of particle transfer by performing simulations of arrests by special force police units, according to both low and high contamination scenarios. The results show that secondary transfers of GSR during these simulations are in most cases not negligible, even for the low contamination scenario. This is especially apparent on the vests of the target persons, with an average of 7 GSR particles (2 PbBaSb and 5 TiZn) found on the stubs used on these materials. Of course, the major contamination levels were observed in the case of the high contamination scenario, due to the use of highly contaminated gloves by the police officers during the arrests. Some recommendations are proposed to take into account this risk of contamination and to try to minimize it, or at least to better identify it.     

Computer says no: technology and accountability in policing traffic stops

The Road Traffic Act 1988 gives police in the United Kingdom the power to seize motor vehicles which they have reasonable grounds for believing are being driven without a valid driver??s licence or motor insurance. Drivers may then have to pay a fee to have their vehicles returned. When exercising this power of seizure, the police may rely on information contained on the Police National Computer (PNC) which is linked to the National Insurance Database (NID). Whilst these databases are undoubtedly invaluable in this endeavour, they are not always accurate, and incidents have occurred whereby motorists who are in fact driving with valid insurance have had their vehicles seized and retained. Focusing on the case of Lisa, whose vehicle was wrongly impounded by Merseyside Police in 2007, and other cases, we explore the legitimacy and legality of such activity. We question both the discretionary power of the police in taking such action, and the validity of their (over) reliance on technology. We posit that the taking of money in cases such as Lisa??s is evidence of the turn within public policing towards marketisation, and consider the capacity for harm to innocent individuals and the implications for justice and fairness. Ultimately, we contend that police accountability is compromised and that a new approach is required. We close the piece with some recommendations for improved police practice.     

Fibres used in the construction of car seats — An assessment of evidential value

The evidential significance of car seat fibres has been investigated. Thirty six samples of car seat fabric were examined and the fibres catalogued according to their morphology and characteristics. The majority of car seat fibres were black or grey thick polyester fibres that were either dyed or pigmented. The MSP spectra produced were unlike those usually obtained from black or grey polyester fibres used in clothing. Tapings taken from car seats were examined for car seat fibres, various types were found showing that these fibres are expected to shed from the fabric albeit in low numbers, unless the vehicle is older. No fibres that matched the samples of the car seat fabric were found on the tapings of the car seats. One hundred garments were examined for car seat fibres, 10% of garments had populations of such fibres present and 41% had at least one car seat fibre present. None of these fibres matched the samples of the car seat fabric or those from the car seat tapings.     

Police use of force: a transactional approach

Drawing on Tedeschi and Felson’s () theory of coercive actions for conceptual guidance as well as principles underlying the notion of a force continuum structure (i.e., proportionality and incrementalism), this research examines 3,544 police–suspect encounters from an observational study of the police in an attempt to better understand the transactional process of the police–suspect encounter. Results indicate, within the context of a force continuum structure, that officers escalated the level of force in about one of five encounters involving nonresistant suspects, and de‐escalated the level of force in three of four encounters involving resistant suspects. A series of logistic and multinomial regression models show that a number of factors differentially affect the manner in which officers apply force. The results suggest that before one can begin to judge the appropriateness of police force, one should measure and consider the extent to which force is applied proportionately and incrementally.     

Suspect Demeanor and Arrest: a Triggered Displacement of Aggression Explanation

The evidence that police arrest suspects who display a disrespectful demeanor is mixed. One explanation for these equivocal results may be triggered displaced aggression theory. This theory suggests persons who are provoked to anger internalize their aggression and unleash it later on someone or something that further agitates them. A sample of officers was primed for either a positive or negative affect, presented with a domestic disturbance vignette, and asked to rate their likelihood of making an arrest. In one vignette version the suspect displayed a hostile demeanor and in the other the suspect’s demeanor was neutral. Officers who were negatively primed and encountered the hostile demeanor suspect were most likely to arrest compared to officer in the other conditions.     

Examination of lightbulb filaments after a car crash: difficulties in interpreting the results

A drunk car driver was involved in a fatal crash with a scooter at night. Examination of the lightbulbs from the vehicles revealed some mechanical and analytical incompatibilities. The laboratory's initial observations led to complementary police investigations which finally solved the first incompatibility. The different precautions taken by the technical police investigators on the crime scene finally allowed the forensic scientists to establish the functional state of the lightbulbs during the crash.     

ARREST FOR DOMESTIC AND OTHER ASSAULTS*

We use the National Crime Victimization Survey to examine whether a suspect's relationship to an assault victim affects whether the police make an arrest. The results indicate that in cases of minor assaults the police are less likely to make an arrest when the suspect is an intimate partner of the victim than when the suspect is an identifiable stranger. However, the police are not as lenient when the suspect is an intimate partner as they are when the suspect is someone else the victim knows. Intimate partner suspects avoid arrest in part because they are less likely to commit their crimes in front of witnesses. In addition, victims who know the suspect in any way are reluctant to sign complaints, and this reluctance inhibits arrest. Men are less likely than women to sign complaints, particularly when the suspect is a partner.