Answer: The cofounder of the Black Panther that was convicted for manslaughter was Huey P. Newton.
Step-by-step explanation: Huey P. Newton was a political activist born in 1942. He co-founded, together with Bobby Seale, the Black Panther Party for Self-Defense in 1966. One year after the party was founded, Newton was involved in a shootout, which eventually led him to be accused of killing a police officer. He spent a period of time in prison, but he was later released. However, Newton was murdered in 1989 by a member of the Black Guerrilla Family.