Sex determination from the talus of Koreans by discriminant function analysis

The aims of this study were to investigate the sex discriminating potential of the talus in Koreans and compare this with other analyses in different populations. Statistical analyses were performed using data from nine measurements acquired from 140 tali (70 men, 70 women). The talus of Koreans is dimorphic between sexes in all measurements (p < 0.01). Discriminant function equations were generated by univariate, multivariate, and stepwise methods with a range of accuracy from 67.1 to 87.1%. Stepwise equations of other populations did not discriminate the sex of the Korean sample as accurately as each equation's own accuracies. The variables with high accuracy in this study are useful for sex determination of Koreans on the basis of confirmation of population specificity.     

An explanation for camera perspective bias in voluntariness judgment for video-recorded confession: Suggestion of cognitive frame

Three experiments were conducted to test the hypothesis that difference in voluntariness judgment for a custodial confession filmed in different camera focuses ("camera perspective bias") could occur because a particular camera focus conveys a suggestion of a particular cognitive frame. In Experiment 1, 146 juror eligible adults in Korea showed a camera perspective bias in voluntariness judgment with a simulated confession filmed with two cameras of different focuses, one on the suspect and the other on the detective. In Experiment 2, the same bias in voluntariness judgment emerged without cameras when the participants were cognitively framed, prior to listening to the audio track of the videos used in Experiment 1, by instructions to make either a voluntariness judgment for a confession or a coerciveness judgment for an interrogation. In Experiment 3, the camera perspective bias in voluntariness judgment disappeared when the participants viewing the video focused on the suspect were initially framed to make coerciveness judgment for the interrogation and the participants viewing the video focused on the detective were initially framed to make voluntariness judgment for the confession. The results in combination indicated that a particular camera focus may convey a suggestion of a particular cognitive frame in which a video-recorded confession/interrogation is initially represented. Some forensic and policy implications were discussed.     

Determination and validation of tetrodotoxin in human whole blood using hydrophilic interaction liquid chromatography-tandem mass spectroscopy and its application

A sensitive analytical method was developed for the quantitative determination of tetrodotoxin (TTX), a powerful sodium channel blocker, in human postmortem whole blood. The sample mixture was cleaned up using cation exchange SPE catridge after protein precipitation by methanol and then separated on a PC-HILIC (phosphorylcholine hydrophilic interaction liquid chromatography) column (150 mm × 2.0mm i.d., 5 μm) using a isocratic elution of 1% acetic acid and acetonitrile. The identification of TTX was performed on tandem mass spectrometry with electrospray ionization interface in positive ion mode. The retention time of voglibose (internal standard) and TTX was 5.1 and 6.0 min, respectively. TTX and internal standard (voglibose) were monitored and quantitated using the ion transitions: the respective precursor to product ion combinations, m/z 320/302 for TTX and m/z 268/92 for voglibose in the multiple reaction monitoring (MRM) mode. The recovery of TTX and voglibose was 61.4% and 62.8%, respectively and the good accuracy (97.7-103.9%), linearity (2-1200 ng/mL) and reproducibility were shown in this method. The limit of detection and limit of quantification were 0.32 ng/mL and 1.08 ng/mL, respectively. This method was applied in the case of three fishermen who were poisoned (including one death) by unknown fish on their boat in October 2010. In this case, the levels of TTX were 27.2, 30.0 and 29.7 ng/mL in heart blood, peripheral blood and serum of a victim, were 3.1 and 12.1 ng/mL in peripheral blood and 3.9 and 12.8 ng/mL in serum of two survivors, respectively.     

Application of Micro‐Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy to Ink Examination in Signatures Written with Ballpoint Pen on Questioned Documents

Questioned documents examined in a forensic laboratory sometimes contain signatures written with ballpoint pen inks; these signatures were examined to assess the feasibility of micro‐attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy as a forensic tool. Micro‐ATR FTIR spectra for signatures written with 63 ballpoint pens available commercially in Korea were obtained and used to construct an FTIR spectral database. A library‐searching program was utilized to identify the manufacturer, blend, and model of each black ballpoint pen ink based upon their FTIR peak intensities, positions, and patterns in the spectral database. This FTIR technique was also successfully used in determining the sequence of homogeneous line intersections from the crossing lines of two ballpoint pen signatures. We have demonstrated with a set of sample documents that micro‐ATR FTIR is a viable nondestructive analytical method that can be used to identify the origin of the ballpoint pen ink used to mark signatures.     

Forensic integrity verification of video recordings based on MTS files

Digital video is used in criminal trials as evidence with legal responsibility because video content vividly depicts events occurring at a crime scene. However, using sophisticated video editing software, assailants can easily manipulate visible clues for their own benefit. Therefore, the integrity of digital video files acquired or submitted as evidence must be ensured. Forensic analysis of digital video is key to ensuring the integrity of links with individual cameras. In this study, we analyzed whether it is possible to ensure the integrity of MTS video files. Herein, we propose a method to verify the integrity of MTS files encoded by advanced video coding high definition (AVCHD), which is frequently used for video recording. To verify MTS file integrity, we propose five features. Codec information, picture timing, and camera manufacture/model are modified AVI and MP4-like format video verification features. Group of pictures and Universally Unique Identifier patterns were specifically developed for MTS streams. We analyzed the features of 44 standard files recorded using all recording options of seven cameras. We checked whether integrity can be validated on unmanipulated videos recorded in various environments. In addition, we considered whether manipulated MTS files edited in video editing software could be validated. Experimental results show that all unmanipulated and manipulated MTS files with known recording devices were discriminated only when all five features were checked. These results show that the proposed method verifies the integrity of MTS files, strengthening the validity of MTS file-based evidence in trials.     

Juror adjustments to the reasonable doubt standard of proof

The standard of proof beyond a reasonable doubt is based on the law's primary motivation to avoid false conviction even at the expense of increasing the probability of false acquittal. Individual jurors, however, have common sense motivations to make factually correct decisions by avoiding both types of error. As a result jurors may interpret the standard of reasonable doubt correctly but deviate from that interpretation in predictable ways when they apply the standard in court. This study makes three hypotheses: (1) jurors are less confident when deciding on acquittal than when deciding upon conviction, (2) conviction is associated with a downward adjustment of the interpreted stringency of the standard at the time of application, and (3) a highly stringent interpretation of the standard is associated with a severe downward adjustment of that stringency at the time of application. The study asked 260 juror-eligible participants to examine a trial scenario. The participants first interpreted the stringency of the legal standard on a probability scale. They then judged the probability of the defendant's guilt, decided on a verdict, and rated their confidence in that verdict. The findings strongly supported all three hypotheses. Application and implication of the study were discussed.