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Understanding the physical, chemical and biological changes that occur during the drying of a bloodstain is important in many aspects of forensic science including bloodstain pattern analysis and time since deposition estimation. This research assesses the use of optical profilometry to analyze changes in the surface morphology of degrading bloodstains created using three different volumes (4, 11, and 20 μL) up to 4 weeks after deposition. We analyzed six surface characteristics, including surface average roughness, kurtosis, skewness, maximum height, number of cracks and pits, and height distributions from the topographical scans obtained from bloodstains. Full and partial optical profiles were obtained to examine long‐term (minimum of 1.5‐h intervals) and short‐term (5‐min intervals) changes. The majority of the changes in surface characteristics occurred within the first 35 min after bloodstain deposition, in agreement with current research in bloodstain drying. Optical profilometry is a nondestructive and efficient method to obtain surface profiles of bloodstains, and can be integrated easily into additional research workflows including but not limited to time since deposition estimation. Optical profilometry is a non‐contact tool to scan bloodstains in ambient conditionsDrying phases are observable in small drip bloodstainsSignificant surface morphology changes occur within 35 min after deposition [ABSTRACT FROM AUTHOR]

This work characterizes fundamental features of static drip patterns simulated for forensic bloodstain pattern analysis. The purpose of this study was to determine if and how two independent variables, impact velocity and droplet number, influence the parent stain size, shape and satellite spatter distribution of drip patterns created with whole ovine blood. To do this, 500 drip patterns were created in a controlled environment at five varying impact velocities and ten different droplet numbers on a hard paper surface. Digital images of the dried patterns were processed and analyzed using Fiji (ImageJ). The data collected from each pattern support the hypotheses that drip patterns contain predictable and reproducible elements based on impact velocity and droplet number. Basic fluid dynamic principles demonstrate that the size of the parent stains, as well as the number and distribution of satellite stains increase with increasing Weber number. A decrease in the circularity of the parent stains was also noted. This study provides fundamental qualitative and quantitative data on observable elements of drip patterns that can be used practically by bloodstain pattern analysts for pattern identification and classification. [ABSTRACT FROM AUTHOR]

Purpose – Early research assumed there was a ubiquitous police culture that resisted change and outsiders. Recent scholarship questions this assumption, but most of the studies focussed on the attitudes of street-level police officers. This study examined the attitudes of police supervisors toward the use of volunteers in policing. The purpose of this paper is to examine general police attitudes held by police supervisors within the context of the use of volunteers in policing. Design/methodology/approach – Surveys were distributed to over 400 police supervisors attending the Federal Bureau of Investigation (FBI) National Academy (NA) program. Items used to measure general police attitudes were borrowed from the Project on Policing Neighborhood study. These items were submitted to a factor analysis and three general police attitudes were identified (expectations for citizen involvement, expectations for order maintenance, and expectations for aggressive law enforcement). Other items were constructed to measures several aspects of using volunteers in policing. While the respondents are a convenience sample of police supervisors, they represent police agencies of various size, location, and type. Findings – Expectations for citizen involvement and order maintenance were significantly related to each of the volunteerism variables in ways that suggest openness if not acceptance to the use of volunteers in policing. These results were seen in the bivariate correlations and were sustained in the regression analysis. Police supervisors with an expectation of aggressive law enforcement, however, were not related to any volunteer measures. Research limitations/implications – The sample of police supervisors is a convenience sample of supervisors attending the FBI's NA, and it is likely that the results are not what would be expected from a random sample of police supervisors. Also, the survey instrument offered limited space for items, thus restricting the attitude questions that could be included. Still, these data from a nationwide sample of police supervisors lends support to the body of scholarship questioning the existence of a universal police culture where all police officers see the world the same way. Originality/value – There is a distinct lack of empirical research focussing on police supervisors, and what is available is limited in sample size and generalizability. This study can shed additional light on the salience of a pervasive and singular police culture. Further, an understanding of the attitudes of the police supervisors toward the use of volunteers in policing can be applied to other agencies that want to improve or implement a volunteer program. [ABSTRACT FROM AUTHOR]

Hydrogels are desirable materials to the field of forensic science and offer many advantages for use as tissue simulants in research and training scenarios. In this work, we demonstrate a proof-of-concept study for our biomaterial described as the Calcium-Alginate Tissue Gel (CATG). CATG biomaterials integrate functional DNA strands designed to amplify with known human primer sets for genetic profiling. Our range of CATG materials demonstrate successful DNA extraction, PCR amplification and genotyping when both fresh and aged for 21 days. The rheological properties of the CATGs were measured and the incorporation of DNA into the CATGs was assessed. Overall, the CATGs demonstrated increased viscoelastic behavior with the addition of DNA. In addition, two methods of sampling were considered, where it was found that cutting a sample of the dried CATG produced higher allele peak heights in the genotype compared to swabbing. Overall, our CATG biomaterials can be designed for multiple applications in forensic science with tunable properties for various training and research needs. [ABSTRACT FROM AUTHOR]