A man found dead in January at the West Hollywood home of the Democratic activist and donor Ed Buck died of an accidental methamphetamine overdose — the second man in less than two years to die there that way, the authorities said.

Timothy Dean, 55, was found dead in Mr. Buck’s apartment on Jan. 7, according to the Los Angeles County Sheriff’s Department. In July 2017, Gemmel Moore, 26, also died from an accidental methamphetamine overdose. He was found on a mattress in Mr. Buck’s living room, the authorities said.

Together, the deaths of Mr. Moore and Mr. Dean, who were black, raised suspicions about Mr. Buck, a 64-year-old white man. The families of both men have accused Mr. Buck of preying on gay black men.