The body was found at 3:40 a.m. in the 500 block of North Florence Avenue, the Los Angeles County Sheriff's Department said. Investigators suspect the man was beaten to death.
The man lived with four roommates in a house in the back of the property. The four men were taken to the Monterey Park Police Department for questioning, investigators said.
A 59-year-old man was arrested in connection with the death, according to the sheriff's department. Yao Zhomg Shi was booked on suspicion of murder.
Lyun Chang, who lives in the front house on the property, said the men were drinking. Around midnight, she heard arguing and thumps, she said.
Anyone with information is asked to contact the Los Angeles County Sheriff's Department's Homicide Bureau at (323) 890-5500.
City News Service contributed to this report.