Police officers conducting a welfare check made the discovery on Tuesday. Rich also went by the name of Andre Dupree.
Two days after his body was found, authorities determined Rich had been beaten to death.
"The medical examination was conducted by the coroner's office and at that time, the death was ruled a homicide from blunt force trauma," said LAPD Detective Gus Villanueva.
Anyone with information is urged to call the Los Angeles Police Department at (877) LAPD 24-7.