LOS ANGELES — The gunman who killed four people, including a 9-year-old boy, at an Orange office park locked the gates to the complex with bike cable locks and was armed with a weapon as well as pepper spray and handcuffs, police said Thursday.

Authorities said the shooting occurred inside a business, Unified Homes, and the gunman and the victims were connected through business and personal ties. Wednesday’s attack was not random, they said.

Officers received a call at about 5:30 p.m. of shots fired at the business in the 200 block of West Lincoln Avenue. The officers encountered gunfire when they arrived and opened fire, Orange Police Lt. Jennifer Amat said.

Because the gates were locked, police officers responding to the scene fired through them and wounded the gunman, Amat said. Police had to use bolt cutters to get into the complex.

Officers found two victims in the courtyard, one of whom was the 9-year-old boy, and a woman who had also been shot and was taken to a hospital, where she remains in critical condition. The 9-year-old is believed to be the son of one of the victims who worked at the business.

Calling it a “horrific massacre,” Orange County District Attorney Todd Spitzer said Thursday it appeared that the boy died in the arms of a woman who “was trying to save him.”

Police at the scene found three additional bodies: that of a woman on an upstairs outdoor landing, one man inside an office and one woman inside a separate office.

Police recovered a semi-automatic handgun and a backpack with pepper spray, handcuffs and ammunition, “which we believe belonged to the suspect,” Amat said Thursday.

The victims’ names have not been released because their next of kin have not all been notified, she said. The suspect is Aminadab Gaxiola Gonzalez, a 44-year-old Fullerton man.

Spitzer also noted that the crimes are subject to the death penalty. He has not made a decision about whether to seek death in this case.