ORANGE, Calif. (AP) — A man was charged Friday with murder and attempted murder in a shooting rampage at a Southern California office building this week that left four people dead, including a 9-year-old boy whose mother was critically wounded.

Police have not revealed a motive for Wednesday's attack but said the gunman had targeted the business, Unified Homes, and had personal and business relationships with the victims.

The suspect, Aminadab Gaxiola Gonzalez, is married to a longtime employee of the company, Aleyda Mendoza. It's not known where she was at the time of the shooting.

Mendoza answered the phone and confirmed to The Associated Press she is Gaxiola’s wife. She said she would provide a written statement but did not immediately send one. According to her LinkedIn account she was a broker assistant at Unified Homes since 2011.

Gaxiola, 44, was charged with four murder counts and three attempted murder counts for firing at two officers who were not hit and for critically wounding the boy's mother, authorities said. Bicycle-type locks were used to shut two gates to the business complex before the attack, forcing arriving officers to use bolt cutters to gain entrance.

“The taking of the life of another human being is the most serious of crimes and the slaughter of multiple people while they were essentially locked in a shooting gallery is nothing short of terrifying,” Orange County District Attorney Todd Spitzer said in a statement.

Gaxiola was shot and remained in a hospital in critical but stable condition. Authorities are investigating whether he was wounded by police or self-inflicted gunfire.

He couldn't be arraigned because he was unconscious, and the hearing was delayed until Monday, said Kimberly Edds, a spokeswoman for the district attorney's office.

Ken Morrison, assistant public defender, declined to discuss the charges and urged the district attorney to respect the judicial process and avoid releasing details that could affect his client's ability to have a fair trial.

The shooting in the city or Orange, southeast of Los Angeles, was the nation’s third major mass shooting in just over two weeks. The other shootings — in Colorado and Georgia — left 18 dead.

Authorities identified the people killed in the California attack as Luis Tovar, 50, who owned Unified Homes; Leticia Solis Guzman, 58; and Jenevieve Raygoza, 28, and her brother, Matthew Farias, 9.

Matthew, a third-grader from nearby Santa Ana, was a humble boy who loved bike riding and his dog, said Zef Farias, the boy's uncle. Usually, Matthew was at day care after school but Wednesday afternoon he was with his mother, Blanca Tamayo, who worked at Unified Homes.

She was the only person shot who survived. When police arrived Tamayo was cradling her dead son, Spitzer said.

Matthew “normally doesn’t go there,” Farias said, fighting back tears. “They were just part of the collateral damage."

Tovar had a previous relationship with Tamayo and they were Raygoza’s parents, said Rosie Farias, the boy’s aunt.

“We are devastated and in disbelief,” she said, recalling outings to the beach and bike riding with her nephew. “He was just the brightest star ever. He made all of us happy. He had so much energy.”

Tovar, attended high school in nearby Anaheim and raised his five children in the city, The Orange County Register reported. His daughter, Vania Tovar, told the newspaper that he coached her and her sisters in soccer when they were younger and was active in their lives.

“My dad was the most amazing dad and grandfather," she said, describing him as hilarious and “extremely outgoing, but serious when he needed to be.”

“Our world is shattered," she said.

Gaxiola, from nearby Fullerton, was staying at a motel in the neighboring city of Anaheim and used a rented car to arrive at the office building on Wednesday afternoon. He chained the front and rear gates to the two-story complex and then went into the second-floor offices of Unified Homes, authorities said.

Police released a frame from a security video inside the office. It showed the gunman wearing a bandana over his face, brandishing a semiautomatic handgun and hauling a backpack that contained pepper spray, handcuffs and ammunition, authorities said.

Gaxiola has a limited criminal record. He was charged in 2015 in Orange County with cruelty to a child and other counts. He pleaded guilty to misdemeanor battery and served one day in jail. All other counts were dismissed, and the conviction was expunged in 2017, said Lauren Gold, spokeswoman for the city of Anaheim.