Santa Clara police said Peratrovich threatened his father with a knife after officers responded to reports of a domestic disturbance at an apartment in the 1300 block of Reeve Street at 11:17 p.m. on Oct. 10, police said.
A conflict between Peratrovich and his 66-year-old father had turned violent, and arriving officers attempted to mediate the dispute, police said.
Thinking the fight was over, the officers began to leave, police said.
However, as they were leaving, the men started fighting again and Peratrovich allegedly armed himself with a knife, according to police.
Police said he refused to drop the knife, instead holding it "in a threatening manner" and moving toward his father.
Three officers fired their weapons to prevent the father from being hurt or killed, police said.
Paramedics were called and Peratrovich was pronounced dead at the scene.
The shooting is being investigated by the Police Department and the Santa Clara County District Attorney's Office.
The officers involved have been with the department for 10, 12 and 16 years, respectively.
Anyone with information about the case is asked to contact Detective Sgt. Todd Cummins at (408) 615-4813.