noun
murder victim; body of a murder victim
Refers to the corpse of a person who has been murdered, often used in news reports or police contexts.
警察は公園で他殺体を発見した。
The police found a murder victim's body in the park.
被害者 means 'victim' in a broad sense (crime, accident, etc.), whereas 他殺体 refers to the physical body of a murder victim.
Compound of 他殺 (tasatsu, 'murder') and 体 (tai, 'body').