SAN BERNARDINO, Calif. >> The man who opened fire in a San Bernardino school was a deeply religious Navy veteran who accused his newlywed wife of infidelity.

They had separated and when he failed to win her back, he went to her special-education classroom and fatally shot her and one of the children she taught before turning the gun on himself, police said today.

In the weeks before Monday’s violence, Karen Smith told family members her new husband, Cedric Anderson, had tried to get her to return home and threatened her, San Bernardino Police Chief Jarrod Burguan said. She didn’t take him seriously and thought he was just seeking attention, he said.

Police do not know what triggered the attack or why Anderson chose to shoot Smith at the school, Burguan said, adding that she never shared any information about her marital problems with colleagues.

“She effectively kept her private life private,” Burguan said.

Hundreds of panicked parents descended on North Park Elementary School on Monday, waiting for hours for information on their children in a city that is still on edge 16 months after a terror attack that killed 14 people and wounded 22 others at a meeting of county employees.

Anderson, 53, walked into the special-education classroom and fired 10 shots with a .357 Magnum, targeting his wife but also hitting two of her students.

Killed was Jonathan Martinez, 8, who had a rare genetic condition known as Williams syndrome and had survived heart surgery. A 9-year-old boy also was shot but was in stable condition and in good spirits, watching cartoons in his hospital bed today, police said.

Anderson and Smith had married in late January but separated in mid-March after Anderson accused her of infidelity, leading Smith to move out, Burguan said.

Just weeks before the shooting, Anderson had professed his love to Smith in a series of social media posts, including one that called her an “angel.”

Smith’s mother, Irma Sykes, said her daughter had been friends with Anderson for about four years before they got married.

“She thought she had a wonderful husband, but she found out he was not wonderful at all,” Sykes told the Los Angeles Times.

“She left him and that’s where the trouble began,” Sykes said. “She broke up with him and he came out with a different personality. She decided she needed to leave him.”

Anderson, a self-proclaimed pastor whose Facebook profile is filled with Bible quotes and religious references, had been unemployed but previously held jobs as a maintenance worker, police said.

He had joined the Navy in 1982 and re-enlisted as a reservist from 1987 until 2003, working as a builder, according to military records.

Anderson had been arrested four times since 1982, though none resulted in convictions, Burguan said. Those arrests included one in August 2012 on suspicion of spousal battery and another in May 2013 on suspicion of brandishing a knife, Torrance police Sgt. Ronald Harris said.

Investigators who searched Anderson’s home after the shooting found a note that made reference to the relationship, feeling dishonored and “moving forward with no regrets,” Burguan said. But outside the context of the shooting, nothing about the note would have been alarming, he said.

The slain teacher was remembered today by one school parent as “nothing but good” with the patience and understanding to handle special-needs students.

“She was an excellent teacher,” said Marie Cabreras, who has two young children at North Park and also has an older daughter who was Smith’s student for two years at a nearby high school.

“She loved on kids. Her whole life was surrounded around kids and helping them, and helping them build a future,” Cabreras said.

Teachers hugged one another and wiped away tears as they returned to the school today to retrieve their belongings. It was to remain closed for the remainder of the week.

Ruben Gutierrez, whose 7-year-old grandson Jeffrey Imbriani was friends with Martinez, said the shooting was “just beyond words.” Gutierrez brought his grandson back to the school to show him how community members were coming together after the shooting and to reinforce that the school is safe.

“You know, it’s not a scary place to be, and just kind of help him process more and re-experience what happened to hopefully make this as healthy and experience as can be given the circumstances,” Gutierrez said.