A drop test device to study the variability of residual marks associated with stabbing attacks

The identification of weapons involved in aggravated assaults with bladed weapons, as well as the correlation between bodily injuries and the energy required to produce them, is crucial for accurate prosecution. In murder cases involving knives, crime weapons often leave marks on bones. Therefore, differentiating the marks created by various weapons and understanding the energy involved in the assaults are essential for forensic investigations. This technical note presents a drop test device designed to deliver controlled impacts at specified energy levels. The device allows for the attachment of different weapons and ensures high accuracy in energy delivery, enabling the consistent reproduction of similar stab marks. Additionally, it can be used with various types of weapons, including blunt and sharp tip ones. The functionality of the device was demonstrated through rib stabbing experiments. Different marks were created using two energy levels and two similar weapons to analyse their effects on the resulting stab marks. The drop test device provides a systematic approach for studying stab marks by enabling controlled and repeatable experiments on different materials or tissues. Its ability to replicate injury patterns under controlled conditions offers valuable insights for forensic investigations.