Crime-related Item Research Articles

Familiarity-related filler items enhance the RT CIT, but not the P300 CIT: Episodic vs. Semantic memory protocols

The reaction time-based concealed information test (RT CIT) typically uses three types of stimuli: 1) probe (i.e., crime-related item), 2) irrelevant (i.e., crime-unrelated item) and 3) target (i.e., an irrelevant item assigned a unique response so as to ensure attention to the test). Lukács, et al., (2017) introduced familiarity-related filler items to the RT CIT, enhancing the efficacy of the test for both single and multiple probe (per block) protocols. Our study aims to A) replicate the effects of familiarity-related filler items on the RT CIT, B) use P300 to investigate the mechanisms of the fillers-related enhancement effect on the RT CIT, C) investigate whether these fillers can enhance the efficacy of the typical P300-based CIT, and D) explore the effects of fillers on the semantic and episodic versions of the P300 and RT CITs. We replicated a clear fillers-related enhancement of the RT CIT (N = 38 for Fillers, N = 37 for No Fillers). Semantic and Episodic experiments were enhanced equally-well by filler items. No effect of fillers was observed on P300 amplitude for CIT stimuli, however, an interaction involving P300 latency suggests that fillers facilitated the processing of Semantic information over Episodic information. Our study independently replicates a valuable improvement of the traditional RT CIT, investigates the potential mechanisms of this enhancement effect, and demonstrates important differences between the P300 and RT CITs.

Study of identifying and managing the potential evidence for effective Android forensics

Since the advent of various IoT devices, the need for digital forensics for mobile devices that people use most closely in their daily lives has continued to grow. Besides, as Bring Your Own Device (BYOD) becomes the trend, devices store business-related information as well as privacy. Thus, mobile devices are becoming the most critical evidence of digital forensics. For practical mobile forensics, it is necessary to identify crime-related items among the many files inside the device accurately. Also, various user information for user behavior analysis from these files should be effectively extracted and managed as potential evidence to ensure integrity. This paper proposes an efficient forensics investigation method for mobile devices with Android OS, which holds the highest share in the world among mobile devices. In this paper, we studied data pre-processing (classification and identification of data), data analysis, evidence management, and Android data Taxonomy.

Selective attention, not cognitive load, elicited fewer eyeblinks in a concealed information test

The concealed information test (CIT), a memory detection test, compares physiological responses to crime-related and crime-unrelated items. This study elucidated processes involving spontaneous eyeblinks during the CIT by manipulating participants’ intention to conceal. Thirty-four participants committed mock theft. In the CIT, wherein eyeblinks are measured simultaneously with autonomic responses, the secret group concealed the crime-related item, whereas the no-secret group did not. As a result, heart rate (HR) was modulated by the intention of concealment in autonomic measures, whereas the effect of concealment on the decrease of eyeblinks was not found to be significant. In addition, the latency of the first eyeblink was longer for the crime-related item in both groups. These results imply that CIT eyeblinks mainly involve the process of selective attention for the item, and the latency of the first eyeblink reflects a delay in attentional disengagement from the item. This study also suggested that there is still room for improvement in simultaneously measuring eyeblinks and autonomic responses in the CIT.

The Act of Answering Questions Elicited Differentiated Responses in a Concealed Information Test

The concealed information test (CIT), a psychophysiological detection of deception test, compares physiological responses between crime-related and crime-unrelated items. In previous studies, whether the act of answering questions affected physiological responses was unclear. This study examined effects of both question-related and answer-related processes on physiological responses. Twenty participants received a modified CIT, in which the interval between presentation of questions and answering them was 27s. Differentiated respiratory movements and cardiovascular responses between items were observed for both questions (items) and answers, while differentiated skin conductance response was observed only for questions. These results suggest that physiological responses to questions reflected orientation to a crime-related item, while physiological responses during answering reflected inhibition of psychological arousal caused by orienting. Regarding the CIT's accuracy, participants' perception of the questions themselves more strongly influenced physiological responses than answering them.

"Bottom-up" in situ proteomic differentiation of human and non-human haemoglobins for forensic purposes by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry.

The detection and identification of human blood on crime-related items are of particular relevance to many investigations because shed blood can provide evidence of violent contact between individuals. However, for any detection and identification technique, specificity is a critical performance characteristic to assess; that is, whether the technique has the capability to differentiate between human blood (which usually is of relevance to a criminal investigation) and non-human blood (which usually would not be associated with a crime but may be detected incidentally). Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) approaches using "top-down" (detection of intact proteins) and "bottom-up" (detection of tryptic peptide markers) were used to detect and identify haemoglobin in blood from humans and from a range of Australian native mammals; the technique could be carried out directly on blood stains without the need to extract proteins (i.e., in situ measurement). Imaging of haemoglobin was achieved in bloodied fingermarks, including those that had been enhanced using two "industry standard" fingermark enhancement processes. Differentiation of intact haemoglobin proteins in human and non-human blood using "top-down" MALDI-TOF-MS was difficult. However, in situ "bottom-up" approaches using tandem mass spectrometry (MS/MS) and de novo sequencing of tryptic digest peptides allowed unambiguous differentiation. Imaging mass spectrometry of human haemoglobin, even when it was mixed with animal blood, was achieved in bloodied fingermarks that had been enhanced using two common processes (staining with Amido Black or dusted with magnetic powder) and "lifted" using adhesive tape. The MALDI-TOF-MS-based in situ "bottom-up" proteomic methodology described here shows great promise for the detection of human blood and even imaging of blood in bloodied fingermarks. The approach is sensitive, can differentiate between human blood and that from many animals (including several Australian native animals), and can be implemented after traditional crime scene fingermark enhancement techniques have been carried out.

Tracers as invisible evidence — The transfer and persistence of flock fibres during a car exchange

This study assessed the recovery of flock fibres used as a tracer in a car exchange scenario. Flock fibres were deposited onto a car seat (or model thereof) and their transfer and persistence was investigated after a real or simulated car exchange. The overall aim of this study was to achieve an optimal use of flock fibres as tracers, i.e. to be able to select a fit-for-purpose flock fibre, to be able to predict the amount of flock fibres to be recovered from crime related items, and to be able to use these numbers to exclude accidental uptake. The effect of a number of variables on the transfer and persistence of flock fibres was studied, including flock fibre length, car upholstery, and trousers material. Laboratory based experiments were undertaken first, followed by realistic field based experiments. The flock fibres were captured in a non-destructive manner through fluorescence photography. A Matlab algorithm enabled fast automated counting of flock fibres on the images. Results indicate that an initial rapid loss of flock fibres from garments may be expected as a result of moderate movement. Although the amount of flock fibres to be recovered is affected by the flock fibre length, the type of car upholstery, and the type of trousers materials (if frictional force is taken into consideration), large numbers of flock fibres have been recovered from all target materials throughout the transfer route. These numbers are higher than the amount of flock fibres recovered due to accidental uptake. In conclusion, flock fibres can serve as invisible evidence to reconstruct a series of events.

Direct identification of forensic body fluids using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

The examination of body fluids such as blood, seminal fluid, urine or saliva is a key aspect of forensic science in regards to investigation of crimes against the person such as murder and rape. This article describes a streamlined and simplified approach for the identification of body fluids using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS) that avoids fractionation or isolation of proteins. It is applicable to the examination of microliter quantities (or less) of neat fluids, extracts or suspensions of dried fluids or deposits of fluids in situ on tufts of fibers plucked from fabrics, which has practical application in the examination of crime-related items such as underwear or face masks. Hemoglobin was used as a marker for blood, α-amylase for saliva, semenogelins, prostate-specific antigen and acid phosphatase for seminal fluid and uromodulin for urine. Aged stains were successfully analyzed; blood proteins were easily detected in an 11-year-old blood stain.

Concealed semantic and episodic autobiographical memory electrified

Electrophysiology-based concealed information tests (CIT) try to determine whether somebody possesses concealed information about a crime-related item (probe) by comparing event-related potentials (ERPs) between this item and comparison items (irrelevants). Although the broader field is sometimes referred to as “memory detection,” little attention has been paid to the precise type of underlying memory involved. This study begins addressing this issue by examining the key distinction between semantic and episodic memory in the autobiographical domain within a CIT paradigm. This study also addresses the issue of whether multiple repetitions of the items over the course of the session habituate the brain responses. Participants were tested in a 3-stimulus CIT with semantic autobiographical probes (their own date of birth) and episodic autobiographical probes (a secret date learned just before the study). Results dissociated these two memory conditions on several ERP components. Semantic probes elicited a smaller frontal N2 than episodic probes, consistent with the idea that the frontal N2 decreases with greater pre-existing knowledge about the item. Likewise, semantic probes elicited a smaller central N400 than episodic probes. Semantic probes also elicited a larger P3b than episodic probes because of their richer meaning. In contrast, episodic probes elicited a larger late positive complex (LPC) than semantic probes, because of the recent episodic memory associated with them. All these ERPs showed a difference between probes and irrelevants in both memory conditions, except for the N400, which showed a difference only in the semantic condition. Finally, although repetition affected the ERPs, it did not reduce the difference between probes and irrelevants. These findings show that the type of memory associated with a probe has both theoretical and practical importance for CIT research.

隠匿情報検査における吸気・呼気速度の新たな算出法

The Concealed Information Test (CIT) assesses whether an examinee knows a crime-related item on the basis of response differences between crime-relevant and crime-irrelevant items. One of the effective measures in the CIT is respiratory speed. The respiratory speed has been defined as an average of moving distances of respiration curve in a specified time interval after the item onset. This moving distance differs between parts of a respiratory cycle. Therefore, the calculated respiratory speed is disproportionately affected by how the parts of the respiratory cycles are included in the time interval. To resolve this problem, Matsuda and Ogawa (2011) proposed a weighted average method. This method calculates the respiratory speed per cycle and weighs it with the proportion that the cycle occupies in the time interval. In the present study, we applied the weighted average method to the calculation of the inspiratory and expiratory speed. Using the weighted average method, the discrimination performance of the inspiratory/expiratory speed descriptively increased as compared with using the original method. However, as for the expiratory speed, statistical tests did not find significant differences between the original and weighted average method. These results raise the next issue: The detection method of respiratory cycles should be more sophisticated.

Within‐individual discrimination on the Concealed Information Test using dynamic mixture modeling

Whether an examinee has information about a crime is determined by the Concealed Information Test based on autonomic differences between the crime-related item and other control items. Multivariate quantitative statistical methods have been proposed for this determination. However, these require specific databases of responses, which are problematic for field application. Alternative methods, using only an individual's data, are preferable, but traditionally such within-individual approaches have limitations because of small data sample size. The present study proposes a new within-individual judgment method, the hidden Markov discrimination method, in which time series-data are modeled with dynamic mixture distributions. This method was applied to experimental data and showed sufficient potential in discriminating guilty from innocent examinees in a mock theft experiment compared with performance of previous methods.

A new discrimination method for the Concealed Information Test using pretest data and within-individual comparisons

A latent class discrimination method is proposed for analyzing autonomic responses on the concealed information test. Because there are significant individual differences in autonomic responses, individual response patterns are estimated on the pretest. Then an appropriate discriminant formula for the response pattern of each individual is applied to the CIT test results. The probability that the individual concealed information is calculated by comparing the discriminant formula value of the crime-related item to that of non-crime-related items. The discrimination performance of the latent class discrimination method was higher than those of the logistic regression method and the discriminant analysis method in an experimental demonstration applying the three methods to the same data set.