Atypical stab injury with a rubber tapping knife (‘Kiri-Pihiya’)

Some stab injuries are atypical. However, the careful examination of the injuries provides valuable information which may lead to the identification of the profile of the weapon. The following discussion is based on a fatal atypical stab injury with an unusual knife. An adult male from a rubber cultivation area had an argument with another from the same locality. He was stabbed once on his shoulder and the suspect escaped with the knife. He was rushed to the hospital but was dead on admission. At the autopsy, the shirt worn by the deceased had a patterned cut injury, an inverted ‘Flat bottomed U-shaped’ cut, 2.5cm x 0.5cm. Underlying gaping stab injury on the right shoulder was 2cm x 1.5cm.  The front margin was 2cm and was sharp and taut. Inner and outer ends were 0.5cm each and were perpendicular to the front margin. The rear margin was sharp but lax. On dissection, the track had parallel margins up to the distal end and the width was 2.5cm. It ran forwards and downwards severing the right subclavian artery. The cause of death was haemorrhagic shock due to stab injury. A rubber tapping knife was produced after 3 days. The blade was 9cm x 2.5cm, thin, with a ‘flat-bottomed U-shaped’ cross-section. The edges were parallel with 0.5cm thickness. The distal end was V-shaped. Features of the atypical stab injury were compatible with the rubber tapping knife allegedly used for stabbing. Photographic documentation and familiarity with the injuries caused by atypical weapons that are available in the locality will be helpful in injury interpretation.