Abstract: 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.

Key words: forensic pathology, blood stains, cast-off