De'Jon Packer, 24-year-old a rookie with the San Jose Police Department and a former running back, was found unresponsive March 13 during a welfare check at his Milpitas home.
The Santa Clara County Medical Examiner's confirmed to KNTV on Saturday that Packer died of a drug overdose. The death remains under investigation by Milpitas police.
San Jose police Chief Anthony Mata said his department does not condone drug use and is cooperating with the Milpitas investigation.
Mata said the police department has scheduled substance abuse prevention training for personnel and is offering emotional support services for officers.
"We need to be mindful of the fact that we are not immune to issues that plague society, in this case substance abuse. As humans we are not perfect, and mistakes will be made," Mata said. "Any allegation of illegal drug use by a San Jose Police officer is concerning. There are no free passes for police officers, and we will not make excuses."
Packer was a star running back at San Jose State University before becoming a police officer.
"We all loved DeJon Packer and we will miss his infectious smile," SJSU football coach Brent Brennan said in a statement.
The Associated Press contributed to this report.