Los Angeles County sheriff's Deputy Guillermina Saldana said the teenager called 911 just after 9 p.m. Wednesday to report the shooting in their Carson home, about 20 miles south of downtown Los Angeles.
He was arrested Thursday morning and was being questioned at dawn at the Carson sheriff's station, Saldana said. No motive was released.
The boy's 40-year-old father, a U.S. Immigration and Customs Enforcement agent, was shot in the head in the home's television room. The bullet was fired through a window from the backyard of the home.
The agent was dead when deputies arrived.
The agent's name hasn't been released but the Department of Homeland Security said he was involved in Homeland Security investigations in the Los Angeles area.
