Two-dimensional metric comparison between dynamic bare and sock-clad footprints for its forensic implications – A pilot study

Footprints may be present at crime scenes as physical evidence. This pilot study compares two-dimensional measurements of bare and sock-clad footprints to determine if significant differences or similarities exist. Dynamic footprints were collected from 30 males and 20 females between the ages of 20 and 61?years old (mean of 28.2?years) using the Identicator Inkless Shoe Print Model LE 25P system. A midgait protocol was employed for obtaining footprints. The fifth and sixth footprint of gait were collected for the right and left foot, respectively, in both sock-clad and barefoot trials. The footprint measurements between sock-clad and bare footprints were compared. The results did not indicate any significant difference (p?>?.05) between bare and sock-clad foot length measurements for right or left feet. Significant differences were seen for the width measurements between bare and sock-clad footprints. These findings have forensic implications, particularly in criminal cases where it is unclear if a footprint impression is from a sock-clad foot or a bare foot. This study shows that such a determination is generally not necessary when utilizing two-dimensional measurements for length comparison between a bare and sock-clad footprint. However, if width measurements are being evaluated, the distinction between bare and sock-clad footprints should be considered.     

Two-dimensional linear analysis of dynamic bare footprints: A comparison of measurement techniques

In forensic intelligence-gathering, footprints have been shown to be valued evidence found at crime scenes. Forensic podiatrists and footprint examiners use a variety of techniques for measuring footprints for comparison of the crime scene evidence with the exemplar footprints. This study examines three different techniques of obtaining two-dimensional linear measurement data of dynamic bare footprints. Dynamic bare footprints were gathered from 50 students from a podiatric medical school using the Identicator® Inkless Shoe Print Model LE 25P system. After obtaining 100 bilateral footprints from the participants, the quantitative measurement data were collected by using three different measurement techniques: (i) a manual technique using a ruler (direct technique); (ii) an Adobe® Photoshop® technique; and (iii) a GIMP (GNU Image Manipulation Program) technique. The seven Reel linear measurement methodology was used for producing measurements using these three techniques.This study showed that all the mean bare footprint measurements on the right and left feet obtained using the direct technique were larger than those obtained using GIMP and Adobe® Photoshop® images. Differences were also observed in measurements produced using GIMP software and Photoshop images. However, the differences observed in the three techniques used for bare footprint measurements were not found to be statistically significant. The study concludes that there are no significant differences between the three measurement techniques when applied to two-dimensional bare footprints using the Reel method. It further concluded that any of these measurement techniques can be used when employing the Reel methodology for footprint analysis without significant difference.     

Reliability of a two-dimensional footprint measurement approach

Although footprint evidence can be taken from the scene of a crime, the science underpinning such measurement in forensic science has not been fully explored.A literature search revealed various measuring approaches, all of which demonstrated either little or no measurement rigour in terms of reliability. The aim of this study was to apply a robust measurement approach for testing the reliability of two-dimensional footprint impressions.Three dynamic and three static footprints were taken from the right foot of thirty female and thirty one male volunteers using the ‘Inkless Shoeprint Kit’. The images were digitised. Lengths, widths and angles were measured using a selection of currently employed methods.An investigation of the reliability of the chosen measuring method suggested high intra-rater agreement: for example, the length measurement suggested an intraclass correlation coefficient (ICC) 0.99, 95% Confidence Interval (CI) ? 0.28 to 0.01, standard error of measurement (SEM) 0.07, Limits of Agreement (LOA) ? 0.91 to 0.65.Inter-rater reliability between three operators was also high: SEM ranged from 0.05 mm to 0.07 mm, ICC 0.99.Our study has established a reliable two-dimensional measuring technique that could be used for footprint comparison in further research.     

A comparison of the length and width of static inked two-dimensional bare footprints found on a hard compared to a soft surface

In forensic intelligence-gathering it would be useful to evaluate if there are differences between static inked bare footprints captured on hard surfaces compared to soft surfaces. This was undertaken using samples from 30 undergraduate students. Initially a static footprint was taken for each participant on a hard surface and this was followed by a static footprint on a soft surface. On both occasions, the participants stood on an inkless mat and then on reactive paper, creating a two-dimensional print. The Reel method was used to analyse each footprint and the print was measured to see whether a difference existed between length and width (forefoot and rearfoot width) on a hard surface compared to a soft surface. The conclusion from this study was there is a statistically significant increase in length and width of a static bare footprint on a soft surface as opposed to a hard surface. If a forensic footprint examiner compares static bare footprints found on a soft surface and compares them to a static bare footprint of the same foot taken later, then the increase in both length and width of the footprints on a soft surface should be considered in the evaluation.     

Two-dimensional metric comparisons between dynamic bare footprints and insole foot impressions-forensic implications

Footwear may be found at crime scenes as physical evidence. Such footwear often has impression features of the wearer’s foot on the insole of the shoe. Scientific research and literature have established that footprints are distinct. This study compares two-dimensional measurements on bare footprints to foot impressions on insoles to determine if significant differences or similarities exist. Dynamic footprints were collected from 51 donors using the Identicator® Inkless Shoe Print Model LE 25P system. Seven foot length and width measurements were taken based on the Reel linear measurement method. Footprint measurements between bare footprints and foot impressions on the insoles were compared. Only two differences (p > 0.05) were observed between the various bare footprint and insole foot impression measurements on the right and left side for most of the measurements, CALC (p < 0.001) and A1 (p = 0.04). Bare footprint and insole A5 measurements on the left side were also significantly different (p = 0.015). The results of the study have implications in the forensic analysis of foot impression evidence on insoles in footwear in assisting with identifying the wearer of said footwear. Situations may arise in the forensic context when comparing the foot impression on the insole of footwear to a suspect’s bare footprint or a footprint from post-mortem remains. This study contributes to the scant literature available on the topic and to understanding the similarities and differences observed in the various linear measurements that may be utilized in the comparison process of footprint impressions on shoe insoles to bare footprints.     

Estimation of stature from static and dynamic footprints

The ability to estimate accurately from known parameters is a fundamental aspect of science and is evident as an emerging approach in the area of footprints and stature estimation within the field of forensic identification. There are numerous foot dimensions that have been measured in the literature to predict stature with varying degrees of confidence but few studies have tried to link the strength of estimation to anatomical landmarks. Such an approach is utilised in this study which estimates stature from the right footprints of sixty one adult male and female UK participants. Static and dynamic footprints were taken from each volunteer using the 'inkless paper system'. The prints were digitised and twelve length, width and angle measurements were chosen for the analysis. The highest correlations with stature were shown to be the heel to fourth toe print for the static group of footprints (r=0.786, p<0.01), and the heel to fifth toe print in the dynamic footprints (r=0.858, p<0.01). Collinearity statistics suggest the heel to fifth toe print length measurement is independent and not influenced by any other variables in the estimation of stature for the dynamic prints. Linear regression equations for this measurement presented the smallest standard error of estimate (SEE) and highest shared variance (R(2)) of all included variables (SEE 4.16, R(2) 0.74). Our study discusses a potential anatomical explanation as to why the lateral border of the foot and hence the impression it makes upon a hard surface, is a more stable indicator in the estimation of stature. The investigation recommends the use of Calc_A4 and Calc_A5 length measurements when estimating stature from footprint impressions.     

Application of non-contact scanning to forensic podiatry: A feasibility study

Foot impression evidence recovered from crime scenes can be available in the form of barefoot prints, sock-clad footprints, or as impressions within footwear. In some cases, suspects leave their footwear at the scene of the crime, and the insoles from the footwear can be important in linking a person to the footwear. The application of 3D data-collecting technology is becoming more and more popular within forensic science and has been used to recover footwear impression evidence. The present study is a feasibility study to discover if 3D data capturing devices can be applied to insoles; to capture the footprint impression for measurement using the Gunn method (a method used in forensic podiatry casework). Three different methods of data capture were conducted; Adobe Photoshop, MeshLab, and calipers used directly on the insole. Paired t-tests and Intraclass Correlation Coefficient (ICC) were conducted for all three data capture methods. Seven measurements used in this study were significantly different across all three methods. ICC scores were moderate to excellent for the Photoshop method, poor to good for the 3D method, and moderate to excellent for the Direct method.     

依据手足印推算身高体重的可行性研究

目的探讨身高、体重与足迹、手印长宽的关系,有助于利用犯罪现场的手印、足迹推断遗留人的身高与体重。方法通过足迹、手印的捺印和测量,大量地收集样本足迹、手印与身高、体重等数据,借助SPSS数理统计软件,进行一元线性回归分析。结果分别建立了由左右足迹、手印全长、掌宽推算身高与体重的十个一元线性回归方程,并对依据左、右侧指标分别推算结果的可靠性进行比较研究。结论可利用回归法由足迹、手印来推算身高、体重。在左右两侧足迹、手印都可利用的情况下,推断身高时应优先选用右侧;推断体重时应优先选用左侧。     

回归法推断手印和足迹与身高和体重的关系

目的探讨身高、体重与足迹、手印长宽的关系。方法通过足迹、手印的捺印和测量,大量地收集样本足迹、手印与身高、体重等数据,借助SPSS数理统计软件,进行一元线性回归分析。结果分别建立了由左右足迹、手印全长、掌宽推算身高与体重的10个一元线性回归方程,并对依据各个指标分别推算结果的可靠性进行比较研究。结论本研究建立的回归方程可用于山东地区部分人群的身高与体重推算;依据足迹较依据手印推算身高体重结果更可靠;在左右两侧足迹、手印都可利用的情况下,推断身高时应优先选用右侧;推断体重时应优先选用左侧。     

A New Method for the Characterization of the Degree of Fire Damage to Gypsum Wallboard for Use in Fire Investigations

A new method to characterize the degree of fire damage to gypsum wallboard is introduced, implemented, and tested to determine the efficacy of its application among novices. The method was evaluated by comparing degree of fire damage assessments of novices with and without the method. Thirty-nine “novice” raters assessed damage to a gypsum wallboard surface, completing 66 ratings, first without the method, and then again using the method. The inter-rater reliability was evaluated for ratings of damage without and with the method. For novice fire investigators rating degree of damage without the aid of the method, ICC(1,2) = 0.277 with 95% CI (0.211, 0.365), and with the method, ICC(2,1) = 0.593 with 95% CI (0.509, 0.684). Results indicate that the raters were more reliable in their analysis of the degree of fire damage when using the method, which support the use of standardized processes to decrease the variability in data collection and interpretation.     

利用残缺赤足足迹推算身高

目的由于主客观条件的影响,犯罪现场中常见的足迹多为不完整的残缺足迹,如何能够有效地利用残缺足迹,对案件破获往往具有至关重要的作用。方法从残缺赤足足迹的反映形态出发,选择足迹中明显、稳定的特征点,确定特征量,通过数理统计分析,建立残缺赤足足迹推算身高的经验公式。结果在4个特征量中,跖前缘突点到跟后缘突点的距离与身高的相关性最好,跖内、外缘突点到跟后缘突点的距离与身高具有一定的相关性。结论根据现场残缺赤足足迹的反映情况,也可以近似推断嫌疑人的身高特点,为侦查提供方向。     

In the eye of the beholder? An examination of the inter-rater reliability of the LSI-R and YLS/CMI in a correctional agency

PurposeTo examine the inter-rater reliability of two risk assessment tools: The Level of Service Inventory-Revised (LSI-R) and the Youth Level of Service/Case Management Inventory (YLS/CMI).MethodsTwo identical experiments are reported. For both studies, a random sample of 10 offenders were interviewed and videotaped with each tool (totaling 20 offenders). The tapes were then shown to a random selection of 20 raters (for a total of 40 raters) employed at a state agency. The fully-crossed design allowed each of the raters to rate the each of the cases, resulting in 200 total risk score observations for each tool. Inter-rater reliability analyses were then conducted.ResultsThe LSI-R demonstrated adequate to fair reliability, with certain domains showing lower reliability. Overall, the LSI-R had an ICC of .65. The YLS/CMI demonstrated higher reliability (ICC of .78). In addition, for the LSI-R study, comparisons were made between staff raters who work in a facility versus those in the community (e.g., probation officers). For the YLS/CMI study, comparisons were made between incarcerated offenders versus probationers. Neither comparison yielded consistent differences.ConclusionsThe YLS/CMI is generally reliable. The LSI-R showed less reliability. However, each study showed certain domains with less than ideal reliability.     

A preliminary study investigating the overlay method in forensic podiatry for comparison of insole footprints

The overlay method is used in forensic podiatry to compare the shape, position, and overall fit of features between questioned and reference footprint evidence. However, the scientific foundation underpinning its validity in the comparison of insole footprints is not fully understood because of a lack of published data defining its statistical operating parameters. A review of literature revealed its subjective nature with little scientific validation, limited only to face validity.The aim of this study investigated strength of agreement between three expert footprint examiners’ overlay comparisons of ten reference insole footprints using Cohen’s weighted kappa (K_w). Validity of method was explored using measures of sensitivity, specificity, false positive rate (FPR), false negative rate (FNR), receiver operating characteristic (ROC) curve and area under the ROC curve (AUC). Results showed two examiners demonstrated high inter-rater consistency between their overlay comparisons (K_w: 0.981; 95 %CI: 0.943 to 1.020 for Rater1 v Rater2) whilst one examiner did not (K_w: 0.340; 95 %CI: 0.148 to 0.532 for Rater1 v Rater3; K_w: 0.310; 95 %CI: 0.100 to 0.519 for Rater2 v Rater3). Validity was investigated using a conclusion scale in a verbal expressions table to indicate support or rejection of compatibility of footprints between one questioned insole and ten reference insoles. Data analysis indicated validity as follows: Sensitivity: 77.8 %, Specificity: 61.9 %, FPR: 38.1 % and FNR: 22.2 %. ROC analysis corroborated this finding. AUC was calculated at 0.762 or 76.2 % indicating an ‘acceptable’ measure of overall accuracy of the overlay method for insole footprint comparison. Findings provide novel data supporting previous suggestions that the overlay method should not be used in isolation to compare insole footprints. Data also offers insight into the scientific foundation of this method, whilst highlighting its limitations and providing some implications and recommendations for forensic podiatry practice.     

The contact area of static and dynamic footprints: Forensic implications

When found at crime scenes, footprints may be evidentially valuable and can assist with the identity of a perpetrator based on their features and/or measurements. Footprints can be either static (made while standing) or dynamic (made while walking). While extensive research has been performed on the linear measurements obtained from static and dynamic footprints, research on the comparisons between the contact area of static and dynamic footprints in the forensic context are limited. The present study compares the contact area of static and dynamic bare footprints to determine if statistically significant differences exist between the two. Static and dynamic footprints were obtained from a sample of randomly-selected 461 Jatt Sikh adults (230 males and 231 females) of Indian origin between the ages of 19 and 32 years. The footprint contact area was calculated from each footprint (excluding the toes) using a PedoGRID® sheet. No statistically significant differences were observed between the contact area of static and dynamic footprints for each foot among males and females. However, statistically significant differences between both the sexes were found in the footprint contact areas of both footprint types. The right dynamic footprint contact area was found to be the most predictive measurement for classifying and estimating sex from a footprint’s contact area. The study has implications in the analysis of footprints recovered from crime scenes.     

Age-related factors in the relationship between foot measurements and living stature and body weight

The measurements of feet and footprints are especially important in forensic identification, as they have been used to predict the body height and weight of victims or suspects. It can be observed that the subjects of forensic-oriented studies are generally young adults. That is to say, researchers rarely take into consideration the body's proportional changes with age. Hence, the aim of this study is to generate equations which take age and sex into consideration, when stature and body weight are estimated from foot and footprints dimensions. With this aim in mind, we measured the stature, body weight, foot length and breadth, heel breadth, footprint length and breadth, and footprint heel breadth of 516 volunteers (253 males and 263 females) aged between 17.6 and 82.9 years using standard measurement techniques. The sample population was divided randomly into two groups. Group 1, the study group, consisted of 80% of the sample (n = 406); the remaining 20% were assigned to the cross-validation group or Group 2 (n = 110). In the first stage of the study, we produced equations for estimating stature and weight using a stepwise regression technique. Then, their reliability was tested on Group 2 members. Statistical analyses showed that the ratios of foot dimensions to stature and body weight change considerably with age and sex. Consequently, the regression equations which include these variables yielded more reliable results. Our results indicated that age and sex should be taken into consideration when predicting human body height and weight for forensic purposes.     

Internal Consistency and Factor Structure of the Revised Conflict Tactics Scales in a Sample of Deaf Female College Students

The Revised Conflict Tactics Scales (CTS2) is currently the most widely used measure for identifying cases of intimate partner violence within the hearing population. The CTS2 has been used successfully with individuals from various countries and cultural backgrounds. However, the CTS2 had not yet been used with Deaf individuals. The goal of the present study was to investigate the internal consistency reliability and the factor structure of the CTS2 within a sample of Deaf female college students. Psychometric analyses indicated that subscales measuring Victimization of Negotiation, Psychological Aggression, Physical Assault, and Injury proved both reliable and valid in the current sample. Three subscales did not evidence reliability and the factor structure was not valid for Perpetration items.     

A New Approach of Juvenile Age Estimation using Measurements of the Ilium and Multivariate Adaptive Regression Splines (MARS) Models for Better Age Prediction

Juvenile age estimation methods used in forensic anthropology generally lack methodological consistency and/or statistical validity. Considering this, a standard approach using nonparametric Multivariate Adaptive Regression Splines (MARS) models were tested to predict age from iliac biometric variables of male and female juveniles from Marseilles, France, aged 0–12 years. Models using unidimensional (length and width) and bidimensional iliac data (module and surface) were constructed on a training sample of 176 individuals and validated on an independent test sample of 68 individuals. Results show that MARS prediction models using iliac width, module and area give overall better and statistically valid age estimates. These models integrate punctual nonlinearities of the relationship between age and osteometric variables. By constructing valid prediction intervals whose size increases with age, MARS models take into account the normal increase of individual variability. MARS models can qualify as a practical and standardized approach for juvenile age estimation.     

SCAN as an investigative tool

Scientific content analysis (SCAN) is a technique that claims to enable the detection of deception in written statements. The underlying assumption is that statements of self-experienced events differ in several ways – such as liveliness and concreteness – from imaginary statements. It is used in many countries as an investigative tool. Nevertheless, little research on the reliability and validity of the SCAN technique is available. In this paper, two studies are presented. The first study focuses on the accuracy of SCAN to detect deception by three groups of raters with a different level of experience. This study shows a lack of validity of SCAN. Study 2 investigated the inter-rater reliability as a possible explanation for the poor validity results, and found little agreement between raters in identifying SCAN criteria. Overall, results indicate that the psychometric qualities of SCAN as an investigative tool is insufficient for use in police practice.