Officers found Frasno's body at Contra Loma Regional Park at about 11:20 p.m., East Bay Regional Park District police said.
Officers removed the man from the lake and gave him immediate medical assistance, but emergency rescue personnel pronounced the man dead at the scene, according to police.
Frasno was in the Bay Area visiting family, police said.
The East Bay Regional Park District Police Department, Contra Costa County Sheriff's Office and the Antioch Police Department also responded to the scene, according to police.
Anyone who was in the area is asked to contact the East Bay Regional Park District Police Department investigations unit at (510) 690-6549.
To make an anonymous tip, call the East Bay Regional Park District confidential tip line at (510) 690-6521.