We report 2 cases in which catheter guide wires were useful for detection of vascular injury site. Case 1: A woman was died of hemorrhagic shock after being slashed at the extremities, but the vessels were so collapsed that it was not easy to find the injured site. After a wound track on the left forearm was cut open and a guide wire was inserted, the injury site was detected expeditiously at the left radial artery. Case 2: A woman was stabbed and died of hemorrhagic shock. An autopsy revealed 2 stab wounds in the back, one of which made a cut in the left lung. The wound track was cut open, and the injured vessel was revealed. It was too small in diameter to macroscopically determine whether the injured branch arose from, and so a guide wire was introduced from the injured site, and the injured vessel was easily determined to be a branch of the left pulmonary artery. Guide wires have many features, such as elasticity, flexibility, and hydrophilicity, which are considered to be applicable to forensic uses. The guide wire technique is easy, less invasive, highly vasoselective, and reproducible in identifying vascular injury sites.