Person identification by gait analysis and photogrammetry

Surveillance images from a bank robbery were analyzed and compared with images of a suspect. Based on general bodily features, gait and anthropometric measurements, we were able to conclude that one of the perpetrators showed strong resemblance to the suspect. Both exhibited a gait characterized by hyperextension of the leg joints, and bodily measurements did not differ by more than 6 mm on average. The latter was quantified by photogrammetry: i.e., measuring by using images of the perpetrator as captured by surveillance cameras. Using the computer software Photomodeler Pro, synchronous images from different cameras were compared and concurrent body features were identified. The program could then render the perpetrator as a three dimensional, high-precision, scalable and measurable object.     

Variability of bodily measures of normally dressed people using PhotoModeler Pro 5

Photogrammetry is used in forensic science to help identify perpetrators from crime scenes by way of surveillance video, but the reproducibility of manually locating hidden body-points such as the joints remains to be established. In this study, we quantified the inter- and intra-observer variability of bodily measures of clothed individuals in two different poses and examined whether body segment lengths could be used to distinguish between people of similar stature. Stature was reproduced within +/-1.5 cm in both the intra- and inter-observer study. Segment lengths were best reproduced when flexion in the joints was present in the intra-observer study, but only the length of the trunk could be used to distinguish between people of similar height. The reproducibility between the two poses was low. Other measures than stature should be used with caution and with the perpetrator and suspect in the same pose. Consistent guidelines for locating body-points should be developed.     

共同实行犯中的身份问题

在共同犯罪中，无身份之人能否与有身份之人构成身份犯的共同实行犯，历来争议较大。对于共同实行犯与身份问题，应当从复行为犯的理论出发，针对身份犯的不同情况，首先确认某一真正身份犯是复行为犯，其次确认该复行为犯的部分实行行为具有身份的可替代性，只有两个条件都具备，无身份之人才能与有身份之人构成共同实行犯。     

Influence of Velocity on Variability in Gait Kinematics: Implications for Recognition in Forensic Science

Closed circuit television (CCTV) footage is often available from crime scenes and may be used to compare perpetrators with suspects. Usually, the footage comprises incomplete gait cycles at different velocities, making gait pattern identification from crimes difficult. This study investigated the concurrence of joint angles throughout a gait cycle at three different velocities (3.0, 4.5, 6.0 km/h). Six datasets at each velocity were collected from 16 men. A variability range VR throughout the gait cycle at each velocity for each joint angle for each person was calculated. The joint angles at each velocity were compared pairwise, and whenever this showed values within the VR of this velocity, the case was positive. By adding the positives throughout the gait cycle, phases with high and low concurrences were located; peak concurrence was observed at mid‐stance phase. Striving for the same velocity for the suspect and perpetrator is recommended.     

Locard's Principle of Exchange,Dental Examination and Fragments of Skin

The transfer of materials between victim and perpetrator was first reported by Locard in the nineteenth century. While in recent years DNA testing has been very successful in matching biological material from crime scenes to perpetrators, the following cases demonstrate that other more time‐honored methods remain useful. Two cases of lethal assault are reported where the victims had bitten their assailants resulting in fragments of the perpetrators’ skin being wedged between their teeth which were discovered during post mortem oral examinations. As the fragments were able to be matched to injuries in the perpetrators, identification was established prior to confirmatory DNA testing. In case 1 a criminal conviction for manslaughter resulted, and in case 2 the identity of the assailant was confirmed. Examination of a properly exposed and illuminated oral cavity may provide useful evidence in assault cases. These cases represent an unusual dental variant of Locard's principle.     

Obtaining confidence intervals and Likelihood Ratios for body height estimations in images

In forensic practice, height estimations on perpetrators visible in video footage from surveillance cameras are regularly requested. There are several ways to do this. Insight is gained into the difference between actual and measured heights by taking validation measurements of a number of test persons. Variation between actual and measured heights is decomposed into a systematic part (because of height loss by pose, 3D modeling of the scene of crime, operator biases) and a random part (due to natural variation). On this basis a method is described for obtaining confidence intervals for the height, including head- and footwear, of questioned persons in images. Since the number of test persons is usually limited, the result is in terms of the Student's t distribution. In addition, for cases in which a suspect is available, an expression is obtained for the Likelihood Ratio (LR), measuring the strength of evidence of resemblance of actual height of the suspect and measured height of the perpetrator. The Likelihood Ratio depends both on the rarity of the estimated perpetrator's height and its closeness to the suspect's height. Technical theorems included may be relevant for other forensic areas as well.     

Multiple perpetrator sexual assault: how does it differ from assault by a single perpetrator?

Research that attempts to identify characteristic features of multiple perpetrator sexual assault (MPSA) is limited. This study compared demographic and assault related characteristics of 135 cases of MPSA with 139 cases of single perpetrator sexual assault (SPSA) reported to the Haven sexual assault referral centre, Camberwell, London, over a 4-year period, and aimed to identify any unique features of MPSA victims, perpetrators and assault type. Victims of MPSA were younger, less likely to be White, more likely to report previous self-harm and more likely to sustain injuries than victims of SPSA. Multiple perpetrators were younger, less likely to be White and more likely to be strangers to the victim than single perpetrators. The nature of the assault was different in single and multiple perpetrator cases; in MPSA, there were more completed rapes and more multiple rapes, and perpetrators were more likely to meet the victim in an outside location before carrying out the assault in a place of residence that was not the victim's. These findings add to a scant but growing evidence base.     

Reconstructing and sequencing behaviours in multiple perpetrator rape

Abstract

Much of the existing knowledge base of multiple perpetrator rape (MPR) comes from studies undertaken more than 20 years ago, and thus fails to integrate contemporary perspectives on sexual violence. The current study used Grounded Theory methodology to construct a holistic model of MPR from 15 victim accounts. The model of multiple perpetrator rape (MMPR) included both the actions of the perpetrators and the reactions of the victim in a temporal sequence of 13 categories, 9 of which had sub-categories that allowed for individual differences. Broad themes of MPR were then explored using a total of 101 cases. Each case was coded in the 9 sub-categories where individual differences were allowed from the model. An associative analysis of these sub-categories was then performed using Smallest Space Analysis. Two dominant themes were displayed. The Manipulate theme included two perpetrators who offended sequentially and socialised with the victim. The Force theme did not involve any social interaction, as the force and teamwork of the group enabled the victim to be physically overpowered.     

Sexual abuse of vulnerable young and old men

During a 4-year period, aggregated data from Adult Protective Services case files in Virginia revealed 17 cases of sexually abused young, middle-age, and old men. The most common types of sexual abuse across age groups involved instances of sexualized kissing and fondling and unwelcome sexual interest in the individual men's bodies. The majority of alleged perpetrators were male; they typically were similar in age to the men and resided in the same residential facility. In none of the cases was the alleged perpetrator prosecuted. Only two of the men continued to be at risk of further sexual abuse by the alleged perpetrator. Implications of these data for future research and practice include a need for studies that focus on differences between male and female victims, especially concerning investigations and interventions, and for training on reporting and intervention for facilities and agencies and organizations working with victims and alleged perpetrators.     

A Comparison of Domestic and Non-Domestic Homicides: Further Evidence for Distinct Dynamics and Heterogeneity of Domestic Homicide Perpetrators

To facilitate a deeper understanding of domestic homicide (DH), the correctional files of 37 male DH perpetrators were examined. Victim, perpetrator and offense characteristics were compared against those from 78 non-domestic homicide perpetrator files to elucidate distinct dynamics. Risk factors preceding DHs were identified retrospectively using the revised Danger Assessment (DA; Campbell et al. 2009), and the role of psychopathy was explored via the Psychopathy Checklist-Revised (Hare 2003). DHs exhibited distinctive dynamics, especially in terms of perpetrators’ predominant drives to inflict harm out of proprietary revenge. Most DHs did not occur “out of the blue”, as 82.9 % of cases showed elements of planning; and 86.5 % were identified as a homicide risk according to the revised DA. Psychopathic DH perpetrators were less likely to act suicidal prior to homicides and more likely to kill in a dispassionate, premeditated and gratuitously violent manner. The findings underscore the importance of coordinated community responses.     

The spectrum of sexual abuse in daycare: An exploratory study

Findings from an exploratory study of 48 children sexually abused in daycare centers and daycare homes are presented. About two thirds were female and one third male. Approximately half of victims were maltreated by a single perpetrator and about half by more than one perpetrator, in the latter instance almost always by both men and women. On average, the children were subjected to 5.3 types of sexual abuse, experienced 2.1 different sorts of threats to obtain their cooperation or prevent disclosure of their victimization, and suffered from 3.7 symptoms regarded as sequelae of sexual abuse. Differences in the characteristics of offenders, victims, the sexual abuse, threats, and sequelae were found based upon the daycare context, that is, whether children were victimized in a center with multiple perpetrators, a center with a single perpetrator, or a daycare home.     

The utilization of forensic science and criminal profiling for capturing serial killers

Movies and nightly television shows appear to emphasize highly efficient regimens in forensic science and criminal investigative analysis (profiling) that result in capturing serial killers and other perpetrators of homicide. Although some of the shows are apocryphal and unrealistic, they reflect major advancements that have been made in the fields of forensic science and criminal psychology during the past two decades that have helped police capture serial killers. Some of the advancements are outlined in this paper. In a study of 200 serial killers, we examined the variables that led to police focusing their attention on specific suspects. We developed 12 categories that describe how serial killers come to the attention of the police. The results of the present study indicate that most serial killers are captured as a result of citizens and surviving victims contributing information that resulted in police investigations that led to an arrest. The role of forensic science appears to be important in convicting the perpetrator, but not necessarily in identifying the perpetrator.     

An examination of the psychological aspects of bite marks

The intent of this paper is to present some psychological threads which appear to be operative for the perpetrator of bite marks. In the catalogue of multiple motivations, there appears to be a current theme of power, control, potency, and the attempt to have a psychological symbolization of the perpetrator's omniscient capacity for absorbing life essences. In an examination of these highly complex needs, the modern perpetrator appears to act out consistently with cultural biases coupled with immediate psychological needs which have pressed for expression. Due to a pattern of psychologically expressed ritualism, the perpetrator will often inadvertently leave important psychological clues at the crime scene. The attack style, mode of death, characteristics of the victim, etc.--these components reveal the information on the type of psychological needs that the perpetrator is trying to satisfy. In the cases of bite marks associated with violent crime, it becomes crucial to an "investigator" what type of personality characteristics are welded together to form this kind of need complex. After reviewing cases reported in the literature and after conducting psychological interviews with perpetrators, three major groups of perpetrators seem to be apparent. The first group is motivated out of an anger track, the second group is motivated out of sadistic biting, and the third is out of the more traditional "cannibal complex" motif.     

Attributions about perpetrators and victims of interpersonal abuse: results from an analogue study

This analogue study (written vignettes and videotapes) examines the influence of victim-perpetrator relationship (spouse or acquaintance), sex of perceiver, and type of abuse (psychological vs. physical) on attributions about victims and perpetrators of domestic abuse. College student participants (73 men, 108 women) were randomly assigned to condition. As expected, type of relationship influenced observer perceptions. Specifically, participants rated the victim of marital violence as more psychologically damaged and disturbed by the abuse than the victim of acquaintance violence. Furthermore, interaction effects showed that men, more than women, rated the actions of the married perpetrator as more of a victim's rights violation than the actions of the acquaintance perpetrator. Second, type of abuse was shown to influence perceptions of the perpetrator but not the victim. Sex-of-perceiver effects were also obtained. Women held the perpetrator more responsible and assigned less blame to the victim than did men. Legal and clinical implications are then discussed.     

论公共场所图像监视与公民权利保护——一个框架性说明

公共场所图像监视是以监视社会理论为理论基础的,是现代科技技术发展在监视领域的呈现和利用。公共场所图像监视限定于公共机构在公共场所设置和运转的图像监视,具有维护公共安全的正当性,同时也呈现对隐私权等公民权利的干预性。作为公权力运作的公共图像监视,在法律保留原理下应当受到法律规范,同时也应契合公益、比例和正当程序等原则要求,并建立体系化的公共图像监视的影响评价、设置、管理、利用、救济等具体制度。在多部地方性公共图像监视规范文件的探索下,我国亟待出台统一的公共场所图像监视法（或条例）。     

Variability and Similarity of Gait as Evaluated by Joint Angles: Implications for Forensic Gait Analysis

Closed‐circuit television (CCTV) footage is used in criminal investigations to compare perpetrators with suspects. Usually, incomplete gait cycles are collected, making evidential gait analysis challenging. This study aimed to analyze the discriminatory power of joint angles throughout a gait cycle. Six sets from 12 men were collected. For each man, a variability range VR (mean ± 1SD) of a specific joint angle at a specific time point (a gait cycle was 100 time points) was calculated. In turn, each individual was compared with the 11 others, and whenever 1 of these 11 had a value within this individual's VR, it counted as positive. By adding the positives throughout the gait cycle, we created simple bar graphs; tall bars indicated a small discriminatory power, short bars indicated a larger one. The highest discriminatory power was at time points 60–80 in the gait cycle. We show how our data can assess gait data from an actual case.     

Relationship to Perpetrator and Posttraumatic Symptomatology Among Sexual Abuse Survivors

This study investigated the association of several dimensions of relationship to perpetrator of childhood sexual abuse to posttraumatic symptomatology in adulthood. A structured clinical interview, the Impact of Event Scale, and the TSC-40 were administered to 67 women survivors seeking psychotherapy. The t-tests for significant differences indicated that subjects whose perpetrators were not caretakers experienced higher levels of posttraumatic symptomatology (PTS) in adulthood than those abused by caretakers. No significant differences were found in traumatic symptomatology between those whose perpetrators were family members and those whose perpetrators were not or between those abused by someone in the home and those abused by someone outside the household. Implications for future research and clinical practice are explored.     

Evaluating Stranger and Acquaintance Rape: The Role of Benevolent Sexism in Perpetrator Blame and Recommended Sentence Length

In most jurisdictions, the law does not recognize the distinction between stranger and acquaintance rape. However, these two types of rape seem to elicit different responses from both lay observers and legal practitioners. Two studies investigating the role of benevolent sexism (BS) in accounting for participants' responses to acquaintance vs. stranger rape perpetrators are reported. Participants were presented with vignettes describing either an acquaintance rape or a stranger rape. As predicted, relative to low-BS individuals, participants who scored high in BS attributed less blame (Study 1) and recommended shorter sentences (Study 2) for the acquaintance rape perpetrator. Benevolent sexism was unrelated to reactions to the perpetrator in the stranger rape condition.