Penetrierende Schädelverletzungen mit elektrischen Bohrmaschinen – ungewöhnliche Verletzungsmuster

Zwei außergewöhnliche Fälle von fremdbeigebrachten penetrierenden Kopfverletzungen durch elektrische Bohrmaschinen werden präsentiert. Derartige Abläufe stellen als Tötungsdelikt bzw. versuchtes Tötungsdelikt eine extreme Rarität dar. Wenige Beschreibungen betreffen Suizide, Suizidversuche oder unfallbedingte Verletzungen durch Bohrmaschinen. Im Fall eines 47 Jahre alten Mannes wurde dem Opfer von seiner in Scheidung lebenden Exfrau mit einer ausgeschalteten Bohrmaschine im Schlaf durch das Ohr in den Schädel gestochen. Der Mann überlebte den Angriff. In dem anderen Fall kam es zu einer Auseinandersetzung zwischen zwei jungen Männern, wobei der Beschuldigte seinem Opfer zunächst Messerstiche und anschließend Bohrerverletzungen zufügte. Insgesamt konnten autoptisch drei durch das Auge in das Schädelinnere eindringende Bohrkanäle festgestellt werden. Das Opfer verstarb unmittelbar am Geschehensort.

The effect of bleaching agents on the DNA analysis of bloodstains on different floor coverings

Blood at crime scenes is one of the most significant traces of evidence in investigation proceedings. Cleaning up these traces with household cleaning products, often containing bleaching agents, inhibits or complicates the detection of DNA. In this study, human blood was applied onto different floor coverings (carpet, laminate, parquet, PVC, tile) and subsequently cleaned with water and bleaching agents (hydrogen peroxide, sodium hypochlorite, DanKlorix®, Vanish Oxi Action®) at different times. Samples have been collected afterwards from the floors. The samples underwent a quantitative and qualitative DNA analysis. Cleaning smooth surfaces with water is usually sufficed to prohibit retrieving a DNA profile in most of the cases. Cleaning carpets was more difficult due to their absorbent surface whereas the use of bleaching agents caused an additional reduction of verifiable DNA concentrations. Retrieving partial or complete profiles after the use of bleaching agents was only possible when cleaning with low concentrations of 3% hydrogen peroxide.

In vivo wireless ethanol vapor detection in the Wistar rat

Traditional alcohol studies measure blood alcohol concentration to elucidate the biomedical factors that contribute to alcohol abuse and alcoholism. These measurements require large and expensive equipment, are labor intensive, and are disruptive to the subject. To alleviate these problems, we have developed an implantable, wireless biosensor that is capable of measuring alcohol levels for up to six weeks. Ethanol levels were measured in vivo in the interstitial fluid of a Wistar rat after administering 1 g/kg and 2 g/kg ethanol by intraperitoneal (IP) injection. The data were transmitted wirelessly using a biosensor selective for alcohol detection. A low-power piezoresistive microcantilever sensor array was used with a polymer coating suitable for measuring ethanol concentrations at 100% humidity over several hours. A hydrophobic, vapor permeable nanopore membrane was used to screen liquid and ions while allowing vapor to pass to the sensor from the subcutaneous interstitial fluid.

Cadaver dogs--a study on detection of contaminated carpet squares

INTRODUCTION

Cadaver dogs are known as valuable forensic tools in crime scene investigations. Scientific research attempting to verify their value is largely lacking, specifically for scents associated with the early postmortem interval. The aim of our investigation was the comparative evaluation of the reliability, accuracy, and specificity of three cadaver dogs belonging to the Hamburg State Police in the detection of scents during the early postmortem interval.

MATERIAL AND METHODS

Carpet squares were used as an odor transporting media after they had been contaminated with the scent of two recently deceased bodies (PMI<3h). The contamination occurred for 2 min as well as 10 min without any direct contact between the carpet and the corpse. Comparative searches by the dogs were performed over a time period of 65 days (10 min contamination) and 35 days (2 min contamination).

RESULTS

The results of this study indicate that the well-trained cadaver dog is an outstanding tool for crime scene investigation displaying excellent sensitivity (75-100), specificity (91-100), and having a positive predictive value (90-100), negative predictive value (90-100) as well as accuracy (92-100).

Desorption characteristics of uncoated silicon microcantilever surfaces for explosive and common nonexplosive vapors

We measured the desorption of explosive trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), and hexahydro-1,3,5-triazine (RDX) vapors from piezoresistive silicon microcantilevers under ambient air. Depending on the amount of vapor loaded on the cantilever, TNT desorption took a few minutes to tens of minutes (for nanogram quantities). On the other hand, no significant loss of PETN or RDX was observed after many hours. We also measured desorption of common "nonexplosive" compounds (water, acetone, and ethyl alcohol) and observed that desorption was too fast to be measured. There is a good correlation between the desorption time and the melting point (or the vapor pressure) of a particular substance. In principle, this method can be used to measure desorption rates of various substances from cantilever surfaces.

Application of compact ultrasound imaging device to postmortem diagnosis

In regions with low autopsy rates, forensic examiners often have to rely on external findings. Imaging techniques can assist the external examination and provide a more objective diagnosis. The SonoSite 180, a portable ultrasound device, was used for the examination of dead bodies. The influence of different degrees of decomposition was estimated. Even in cases with intestinal gas formation images of internal organs could be obtained with special techniques. Various pathological findings were detected by ultrasound and verified by autopsy (e.g. pericardial tamponade, cardiac hypertrophy, fatty liver, aortic aneurysm, metastatic liver, etc.). The experiences with the SonoSite 180 are promising. The device can be carried to the death scene or to the morgue and therefore serve as a valuable tool for medicolegal applications.

[Suicidal electrocution using timers. Case reports and review of the literature]

Suicidal electrocution using a time switch is relatively rare. Based on two cases from the authors' own forensic material and seven cases from literature peculiarities regarding the concomitant intake of medicines (benzodiazepines) and alcohol are discussed and comments are made how to proceed in the criminal and forensic investigation of such cases.

[Unintentional gunshot during police intervention]

33 cases of unintentional handgun use by police officers during operation since 1983 in Northern Germany have been evaluated. These cases have been selected from our own investigations and from prosecutors' and police departments' files and records. It was intended to find out criteria for forensic expertise. The unintended use of a handgun was always influenced in a decisive and causal manner by the behaviour of the delinquents (resistance, assault, escape). The confrontation of the police officer with the violence of aggressive offenders was of immediate importance for triggering the shot in various kinds of police operation. Sensorically caused, reflex muscle contractions as a consequence of a great effort, a loss of balance or fright when simultaneously protecting oneself with weapon in hand can be made responsible for the unvoluntary shot. In 10 cases (30%) persons were injured, 2 times lethally. As a whole, the consequences were of random nature, they could be explained by the series of actions in each case. The type and technical state of the weapons in use have not influenced the unintentional use. A behaviour of the police officers offending against the legally required care was stated in two of the investigated cases. Considering our investigations and the many policemen killed in duty we state that securing oneself in time with a weapon at the ready in critical phases of operations cannot be successfully replaced by any other method of self defense.

Skin and soft tissue artifacts due to postmortem damage caused by rodents

Five cases of postmortem bite-injuries inflicted by rodents are presented (five males between 41 and 89 years; three cases caused by mice, one case by rats, one case of possible mixed rodent activity by rats and mice). The study presents a spectrum of phenomenological aspects of postmortem artifacts due to rodent activity to fresh skin and soft tissue: the majority of the injuries have a circular appearance. The wound margins are finely serrated with irregular edges and circumscribed 1-2 mm intervals within, partly showing protruding indentations up to 5 mm. Distinct parallel cutaneous lacerations deriving from the biting action of the upper and lower pairs of the rodents incisors are diagnostic for tooth marks of rodent origin but cannot always be found. No claw-induced damage can be found in the skin beyond the wound margins. Areas involved in the present study were: exposed and unprotected parts of the body, such as eyelids, nose and mouth (representing moist parts of the face); and the back of the hands. Postmortem rodent activity may occasionally be expected on clothed and therefore protected parts of the body. The phenomenon of postmortem rodent activity to human bodies can be found indoors especially under circumstances of low socioeconomic settings; outdoors this finding is particularly observed among fatalities among homeless people.