The accuracy of crime statistics: assessing the impact of police data bias on geographic crime analysis

Journal of Experimental Criminology - Police-recorded crimes are used by police forces to document community differences in crime and design spatially targeted strategies. Nevertheless, crimes...     

Testing the utility of a geographical profiling approach in three rape series of a single offender: a case study

The purpose of the study was to test the potential utility of a geographical profiling approach for three separate series of rapes committed by a single offender. Two different mathematical distance-decay functions using either a normal distribution with a mean distance and standard deviation based on previous research or a truncated negative exponential function based on distances between crime sites in the series under investigation were applied to each of the series giving prioritised search areas the accuracy of which was then assessed. The prioritised area that had to be searched before the home base of the offender could be located varied from 7.60 km(2) or 2.15% of the total search area at its best to 15 1.10 km(2) or 42.66% at its worst for the normal distribution based on previous research and from 42.06 km(2) or 11.88% to no improvement when the truncated negative exponential function was used. The functions used showed less predictive ability when the offender was a commuter. Explanations for the variations in the findings as well as suggestions for improvements were outlined in the discussion.     

Hair testing and self-report of cocaine use

Hair analysis is a useful tool in both clinical and forensic fields: it allows information about drugs of abuse (DOA) consumption to be obtained. However, in spite of analytical results, sometimes patients continue to deny using drugs or, on the contrary, insist on describing themselves as severe drug addicts; indeed there are often considerable difficulties in getting truthful statements about the real amount of drugs used. In this study we have tried to compare cocaine concentration in hair samples with self-reported drug intake. We enrolled 113 subjects (61 Africans, 52 Caucasians) who had been recently sent to jail. They were asked to tell about their use of illicit drugs during the last three months and then submitted to hair analysis. Hair segments (3 cm) were analyzed by GC-MS for amphetamines, cocaine and opiates. Useful data was obtained from 82 subjects, separated into two main groups on account of ethnic origin (African or Caucasian) and divided further into daily, weekly and monthly users. The results showed qualitative results and self-reported consumption to be in good agreement, although the correlation between frequency of consumption and concentration in hair revealed sometimes higher concentrations in contrast with the admission of low consumption. There was a definite separation between occasional and daily use (especially in Caucasian people), while concentrations found where weekly use was reported were more variable. Concentrations of cocaine measured in Africans' hair were much higher than in Caucasians'. Even if this study is exclusively based on self-report, it provides some interesting information in order to differentiate the frequency of consumption, and especially underlines the great importance of ethnic bias on hair analysis.     

An attestation of the spatiality and saliency of police culture: a cross comparison study of croatian and cypriot novice law enforcers

It is often maintained that factors such as the multifarious and exigent nature of the police profession, the diversity of police personnel, and the dissimilar socioeconomic and political settings which surround the sphere of policing, fragment the shared values, beliefs, and norms of police officers. As a result, the spatiality and saliency of such values (police culture), is doubted, if not denied. Such being the case, the article sets out to examine whether or not police culture, as documented to exist in Anglo-American police organisations, is reflected in two disparate settings, namely the Croatian and Cyprus Police. For attesting the foregoing, quantitative research was undertaken in these two settings. Upon analysing the responses of novice law enforcers (n = 185), it was found that the core constituents of police culture (isolation, suspicion, brotherhood, and cynicism), besides cynicism – which was partially supported – manifested in both police organisations.     

A rapid screening procedure for drugs and poisons in gastric contents by direct injection-HPLC analysis

A high performance liquid chromatographic method for toxicological drug screening of gastric content has been developed. The samples were diluted (1:3-1:30) in 0.01 N hydrochloric acid and injected into a reverse phase column for separation by gradient elution. Mobile phase consisted of solvent A (acetonitrile/water 90:10, 0.01 M sodium dodecylsulphate, 0.5% v/v glacial acetic acid) and solvent B (water/acetonitrile 90:10, 0.01 M sodium dodecylsulphate, 0.5% v/v glacial acetic acid); the gradient was programmed from 20 to 80% A in 30 min. The flow was kept constant at 1.5 ml/min. Two home-made internal standards, butyrylsalicylic acid and diacetyltubocurarine with retention times of 5.6 and 21.4 min, respectively, were used. Drugs are identified by matching their relative retention times and UV spectra (200-400 nm) with those contained in a home made library of more than 340 reference compounds (9 analgesics, 22 antidepressants, 30 antihistamines, 14 antihypertensives, 21 antirheumatics, 15 beta-blockers, 9 bronchodilators, 10 Ca antagonists, 14 diuretics, 26 neuroleptics, 25 tranquilizers, and other significant xenobiotic compounds). The fluorometric (FLD) emission spectrum (280-700 nm; excitation wavelength, 230 nm) was used as a further identification. At 50mg/l analyte concentrations, the injection of gastric content after dilution (1:3) produced S/N ratios in the range 8-140. The method is simple, rapid, rather inexpensive and proved to be a useful means of investigation if used in combination with GC-MS screening in blood. On the other hand, the system suffers from a relatively limited sensitivity for compounds with a low UV absorption and from interferences due to the presence in the matrix of some highly UV- and FL-responsive compounds (e.g. tryptophan).     

Should Police Identities Be Disclosed in Anti-riot Operations Transpiring in Cyprus? A Juxtaposition of Novice and Senior Police Constables’ Perceptions

European Journal on Criminal Policy and Research - The article sets out to examine the stances of novice and senior Cypriot law enforcers towards the disclosure of their identities in anti-riot...     

Assessment of sexual interest using a choice reaction time task and priming: A feasibility study

Purpose. We investigated the feasibility of assessing sexual interest in hetero‐ and homosexual men using two information‐processing methods, namely a choice reaction time task and priming. The participants were expected to have longer reaction times for sexually explicit when compared with non‐explicit pictures due to sexual content‐induced delay. In addition, the reaction times of the heterosexual (N=15) and homosexual (N=11) men for pictures corresponding with their sexual interest were compared to pictures not corresponding with their sexual interest. Heterosexual men were expected to have longer reaction times during the presentation of sexually explicit female as opposed to male pictures, whereas homosexual men were expected to have the opposite pattern. Method. The participants were presented either sexually explicit or non‐explicit male and female target pictures (and primes that preceded the targets in random combinations) while simultaneously performing a choice reaction time task in three phases each containing a total of 160 prime–target pairs. Results. Both expectations were confirmed in phase 1 of the study. In phase 2, the means differed in the expected way, but the effects were not significant. In phase 3, the expected effect was moderated by a complex priming effect. Conclusions. The results suggest that the choice reaction time task is a promising way of measuring sexual interest but that questions of habituation should be given more attention in future studies.     

Highly efficient and automated extraction of DNA from human remains using a modified EZ1 protocol

Bones and teeth often represent the only sources of DNA available for identifying human remains. DNA in bones and teeth is generally better preserved than that in soft tissues because of the presence of hard connective tissue with a high level of calcium. Because of the extensive mineralisation, the choice of an efficient DNA extraction procedure is important to minimise the sampling of a high level of minerals and to remove polymerase chain reaction (PCR) inhibitors. Some protocols are available for DNA extraction from bones and teeth as part of the Qiagen EZ1 DNA Investigator Kit using the EZ1 Advanced XL automated purification platform. To improve the efficiency of DNA extraction from skeletal remains, the present study focuses on a modification to these already available protocols. In this study, different bones and teeth collected between 1 and 50 years after death were subjected to DNA extraction using the standard EZ1 protocol, a supplementary protocol, and a modified protocol. The modified approach included a decalcification step, whereas the Qiagen protocols worked directly on non-decalcified powder. In all three procedures, 150 mg samples were used for DNA extraction. We evaluated the quantity of DNA recovered from samples, the presence of any PCR inhibitors co-extracted, the level of DNA degradation, the quality of short tandem repeat (STR) profiles, and the reproducibility of the modified procedure. When compared with the other protocols, the modified protocol resulted in the best recovery of DNA that was free of PCR inhibitors. Additionally, the STR profiles were reliable and of high quality. In our opinion, the decalcification step increases DNA recovery by softening tissues, which allows lysis solutions to act more effectively. Furthermore, the use of two lysis solutions and the variation added to the EZ1 purification step allow for DNA recovery with quality and quantity superior to those of the previously available Qiagen-based protocols. These findings may be helpful solutions to the problems commonly encountered when dealing with difficult samples, such as bones and teeth.

Key points

• Bones and teeth often represent the only sources of DNA for identifying human remains.
• The choice of an efficient DNA extraction procedure is important for maximizing DNA recovery and removing PCR inhibitors.
• This study focuses on modifications to the previously available Qiagen-based protocols.
• The modified protocol enabled the best recovery of DNA, and both quality and quantity were superior to those of the previously available Qiagen-based protocols.
• The STR profiles obtained from samples extracted using the modified protocol were reliable and of high quality.