According to police, a shooting at a Southern California office building today killed four people, including a boy, and wounded a fifth before the gunman was shot by officers.

Officers arrived at a two-story office building on Lincoln Ave in Orange, southeast of Los Angeles, at around 5.30 p.m. local time and heard gunshots, according to Lieutenant Jennifer Amat.

Amat said "an officer-involved shooting occurred" and the victim was taken to the hospital, but she didn't know his condition right away.

According to Amat, the shooting occurred on the second floor of the school. According to news, bodies were found on the second-floor walkway and in a courtyard.

Amat had no information about the altercation, what might have caused the attack, or why a child may have been present at 202 W Lincoln Ave. building. A handful of companies, including an insurance agency, a financial advisory company, a legal services firm, and a phone repair shop, were listed on the outside.

The situation had been stabilized by 7 p.m., and there was no danger to the public, according to police.

Governor Gavin Newsom described the killings as "horrifying and heartbreaking" in a tweet.

"Our thoughts and prayers are with the families who have been affected by this horrific tragedy," he said.

According to the Orange County Register, a Facebook Livestream shared by a resident who lives near the office building shows officers bringing a motionless person out and offering assistance to someone else.

Officers were also seen taking two handguns from a person who was lying on the ground and assisting another person on the Livestream. According to the newspaper, two more people were taken away in handcuffs.

The attacks were the second mass shooting in the United States in as many weeks. Last week, ten people were killed in a Boulder, Colorado, supermarket, and the week before, eight people were killed in three Atlanta-area spas, including six Asian women.

The shooting was the worst in the city since a gunman armed with an assault rifle targeted a California Department of Transportation maintenance yard in December 1997, according to Amat. Before being killed by officers, Arturo Reyes Torres, 41, an equipment operator who had been fired six weeks before, killed four people and wounded others, including a police officer.

Orange is situated 48.28 kilometers southeast of Los Angeles and has a population of around 140,000 residents.