OBJECTIVE: To observe the characteristics of vertical cast-off bloodstain pattern by different hitting-tools. METHODS: The regular hitting tools, a kitchen knife, a dirk, a plane set-hammer and an iron pipe, were selected. At a distance of 30 cm away from the wall, the hitting tool with 5 mL fresh chicken blood made the cast-off bloodstain from top to bottom. Then the holistic distribution characteristics (length, width and density) of cast-off bloodstain and morphology characteristics (length, width and contact angle) of first single cast-off bloodstain were analyzed. RESULTS: The distribution length of cast-off bloodstain formed by dirk was minimum (P < 0.05). The distribution width of cast-off bloodstain formed by kitchen knife was minimum (P < 0.05). Except the pair of kitchen knife and plane set-hammer, the distribution density between each two tools had statistical differences (P < 0.05). The length of first single cast-off bloodstain formed by plane set-hammer was longest compared (P < 0.05). The width of first single cast-off bloodstain had statistical differences between kitchen knife and plane set-hammer, and between dirk and plane set-hammer (P < 0.05). CONCLUSION The type of hitting tool could be inferred by the specific characteristics of cast-off bloodstain pattern formed by every specific type of hitting tool in crime scene.
Blood Stains ; Computer Simulation ; Crime ; Forensic Ballistics/methods* ; Forensic Medicine/methods* ; Humans