Five people are dead, including three children, after an apparent murder-suicide shooting at a church in Sacramento, California, authorities said Monday.

A father walked into a church in the Arden-Arcade neighborhood and shot three of his kids -- all under the age of 15 -- before turning the gun on himself, Sgt. Rod Grassman with the Sacramento County Sheriff's Office said at a press conference.

The shooter had a restraining order against him, Sacramento County Sheriff Scott Jones told reporters, and required supervised visits with his children.

A fire official previously told CNN that the fifth person found dead was identified as the shooter's wife.

Jones separately told reporters the fifth person found dead appeared to be supervising the visit, and that the mother was cooperating with authorities. CNN has reached out to the fire department and sheriff's office for further clarification.

There were other people in The Church in Sacramento at the time of the shooting but none were involved, Sacramento Metropolitan Fire District Capt. Parker Wilbourn told CNN. Most of the others were employees or congregates, he said, and no one else at the scene required medical transport.

It is not known at this time if a service or event was taking place at the church at the time.

The incident is currently being investigated by the Sacramento County Sheriff's Office, which had asked people to avoid the area following reports of the shooting Monday evening.

Gov. Gavin Newsom described the shooting as "another senseless act of gun violence in America."

"Our hearts go out to the victims, their families and their communities," he tweeted. (CNN: Excludes headline)

•File: Law enforcement are seen near a church in the Arden area of Sacramento County on February 28