RIVERSIDE, Calif. — A leader of a Southern California white supremacist group was shot and killed on Sunday at his home here, investigators said.

The victim, Jeff Hall, 32, was a regional director for the National Socialist Movement, a neo-Nazi group based in Detroit.

Mr. Hall, a plumber and the father of five children, was shot at his suburban home on Sunday morning, said Lt. Jaybee Brennan of the Riverside Police Department. Lieutenant Brennan said the police responded to reports of gunshots at Mr. Hall’s home just after 4 a.m. The police later detained Mr. Hall’s son, believed to be 10 years old. The department said no other suspects were being sought.

A neighbor said she saw several guns being removed from the home.

An official with the National Socialist Movement in Southern California said that he had seen Mr. Hall on Saturday night and had planned to have breakfast with him on Sunday.