Estimating the postmortem interval of human skeletal remains by analyzing their fluorescence at 365 and 490 nm.

The study presented here is regarded as a continuation of the experiments of Sterzik et al., who developed a new practical method to distinguish between historical and recent human skeletal remains. Bone cross-sections were illuminated using light with wavelengths of 365 and 490 nm, causing fluorescence. The fluorescence was documented by photography and further analyzed to examine the areal extent of a certain fluorescent color. Contrary to the previous experiments of Sterzik et al., the present study focused on bones with postmortem intervals (PMIs) ≥ 50 years. Therefore, this study fills the gap created by the former study, pointing towards a correlation between the PMI and the areal extent of the fluorescent surface in both tests. The presence of blue and red fluorescent surfaces < 1% indicated a PMI ≥ 50 years. Furthermore, the presence of blue and red fluorescent surfaces > 1% can be regarded as a marker to exclude a PMI ≥ 50 years; in fact, these bones are likely to have a PMI < 30 years.

Visualizing old biological traces on different materials without using chemicals.

During the investigative process that typically follows a criminal act, it may prove necessary to work with and analyze evidence that is not recent but old. This could become necessary, for example, when a crime is discovered some time after it was committed or when a cold case is reopened. Due to this need, the present study focused on the detection and visualization of 2-year-old biological traces. To do so, an alternative light source and different filters were used. The optical behavior of 2-year-old samples of blood, semen, urine, saliva, and sweat located on 19 different materials was documented, analyzed, and compared with the optical behavior of the same samples when they were recent [1].

Bullet fragmentation preceding a contour shot: case study and experimental simulation.

In medico-legal literature, only a small number of publications deal with lethal injuries caused by shots with modified guns. This might lead to the conclusion that such cases are extremely rare. However, there are cases again and yet again. During the investigation process, the modified gun is of particular importance since it can show an unusual ballistic behaviour. The present paper reports on a suicide of a 60-year-old man, committed with a modified revolver and a lead bullet. The man had a single gunshot wound with entrance at the right temporal bone. Autopsy revealed that the bullet had fragmented into two major parts. The smaller one stood outside the cranial cavity and pushed its way alongside between the cranial bone and scalp to its end position in the left temporal area. The bigger part entered the cranial cavity and ended in the left parietal lobe. In shots on ballistic soap and on a head-model, the ballistics of the weapon and lead bullet were characterized. The angle necessary for bullet fragmentation was determined by shots on ballistic soap and turned out to be 55°-60° at a velocity of around 200 m/s. This knowledge was transferred to contact shots on a head-model consisting of a layered polyurethane sphere filled with 10 % ballistic gelatine and covered with a skin-like cap almost all around. The resulting injury pattern corresponded to the one of the suicide person. The bigger bullet part entered the skull while the smaller part pushed its way alongside between skin and skull causing an outer contour shot. Furthermore, the revolver was documented firing off two bullets by one trigger pull-a phenomenon of importance for forensic casework the authors have not found reported in forensic literature.

Estimating the postmortem interval of human skeletal remains by analyzing their optical behavior.

The aim of this study was to figure out a new practically applicable method to distinguish between historical and recent human skeletal remains. Therefore, the optical behavior of bone cross sections was investigated using the combination of two methods: a modification of an already established test (UV-induced fluorescence) and a new method (490 nm-induced fluorescence). We evaluated the areal extent of fluorescence of 30 bone cross sections with known postmortem interval (PMI) using ultraviolet light and 490 nm light. For analysis, the areal extend of fluorescent surface was determined using photos of the samples and an image editing software. The results prove that there is a correlation between PMI and the areal extent of fluorescent surface in both tests. Furthermore, the combination of both methods is a good indicator to distinguish within the forensic relevant post mortem interval between PMI < 30 years and PMI > 30 years.

Reconstruction of crimes by infrared photography.

Whenever blunt or sharp forces are used in a crime, analysis of bloodstain pattern distribution may provide important information for the reconstruction of happenings. Thereby, attention should be paid to both the crime scene and the clothes of everyone involved in the crime. On dark textiles, though, it is difficult or even impossible for the human eye to detect bloodstains because of the low contrast to the background. However, in the near infrared wavelength range, contrast is considerably higher. Many textiles reflect light beyond a wavelength of 830 nm and thus appear light-colored, whereas blood absorbs the light and appears dark. In our studies, a D7000 NIKON reflex camera modified for infrared photography produced high-resolution photographs visualizing even very small spatter stains on dark textiles. The equipment can be used at any crime scene or lab and provides immediately available and interpretable images. Thus, important findings can be obtained at an early stage of police investigations, as two examples (homicide and attempted homicide) illustrate.

Searching for biological traces on different materials using a forensic light source and infrared photography.

Because biological traces often play an important role in the investigation process of criminal acts, their detection is essential. As they are not always visible to the human eye, tools like a forensic light source or infrared photography can be used. The intention of the study presented was to give advice how to visualize biological traces best. Which wavelengths and/or filters give the best results for different traces on different fabrics of different colors? Therefore, blood (undiluted and diluted), semen, urine, saliva, and perspiration have been examined on 29 different materials.

Whiplash-Associated Disorders : Clinical and medico-legal guidelines on the methods of ascertainment.

The manuscript presents the International Guidelines developed by the Working Group on Personal Injury and Damage under the patronage of the International Academy of Legal Medicine (IALM) regarding the Methods of Ascertainment of any suspected Whiplash-Associated Disorders (WAD).The document includes a detailed description of the logical and methodological steps of the ascertainment process as well as a synoptic diagram in the form of Flow Chart.