A domestic shooting in Pleasanton ended with a father dead and his adult son in custody. Lance Chan, 61, was shot on the night of August 15, 2025, after police responded around 9:40 p.m. to reports of gunfire near the 4600 block of Helpert Court. He was found with a gunshot wound, taken to a local hospital, and pronounced dead.

Investigators say an argument inside the family home escalated and detectives focused on Chan’s 28-year-old son, Lucas Chan, who was detained at the scene and later booked on suspicion of murder. Court filings and police statements allege Lucas admitted firing through his bedroom door with intent to kill, striking his father. Officers also found suspected improvised explosive devices, unregistered ghost guns, and a 3D printer, evidence handled with assistance from the Alameda County Sheriff’s EOD team and the ATF.

Lucas Chan remained in custody as the Alameda County District Attorney’s Office charged him with murder and investigators continued processing firearms and explosive-related evidence. Does anyone have information about the household or witnessed activity near Helpert Court that night?