A gangster was brought to the casualty after a fight. He had multiple injuries. Some stab wound were showing 'Fish tailing'. This appearence of the wound is seen in injury with:

When a single-edged weapon is used, the surface wound will be triangular or wedge-shaped, and one angle of the wound will be sharp, the other rounded, blunt or squared off. Blunt end of the wound may have small splits (often in two places) in the skin, so called "fish tailing", if the back edge of the blade is stout. Ref: The Essentials of Forensic Medicine and Toxicology by Dr. K. S. Narayan Reddy, 27th edition, Page 176.