LA CANADA-FLINTRIDGE, Calif. -- A Los Angeles County firefighter shot and killed his wife -- herself a deputy with the Los Angeles County Sheriff's Department who was off duty at the time -- and then himself, officials said Monday.

The killing happened Sunday night at the couple's house in the Los Angeles suburb of La Canada Flintridge, where their 6-year-old son was home, according to sheriff's Sgt. Carmen Arballo.

After the shooting, the firefighter took the boy to his grandparents' home, Arballo said, then drove to a fire department warehouse where he worked about 15 miles away and turned the gun on himself.

"Today is a sad day for all public safety personnel in Los Angeles County," county fire Chief Daryl L. Osby said in a written statement.

Authorities identified the deputy as Cecilia Hoschet, 32, who worked at the county jail's inmate reception centre. She joined the department two years ago, according to the sheriff's department. The firefighter was James M. Taylor, who worked as a paramedic for six years, according to his department.

Sheriff's deputies responded to a 911 call just before 10 p.m. that a woman was screaming inside the home. There they found Hoschet had been shot and killed.

"We lost a wonderful deputy last night," Sheriff Jim McDonnell said in a written statement that described Hoschet's "positive and helpful approach to her work."

The sheriff's department said it recovered a weapon but was not publicly discussing a possible motive.

On Monday, a car in the driveway had a child's seat in the rear and on the front seat a parking receipt dated Sunday from Disneyland.

The Los Angeles Times reported Monday that detectives were investigating the possibility that Taylor used his work radio to tell authorities about his wife's slaying -- and that he was going to kill himself.

According to a scanner recording reviewed by the newspaper, soon after the 911 call, a man got on an emergency services channel and said responders would find one person dead at the home.

"No assailants. You can let them know it's clear," the man continued, before adding that "there's going to be one" more fatality at the fire warehouse in the Pacoima area of Los Angeles. That is where Taylor's body was found.

Sheriff's Deputy Amber Smith would not comment on the report about the radio call, saying the case was still under investigation.