A special needs teacher and an 8-year-old boy were shot and killed in a murder-suicide at a Southern California elementary school, police said Monday.

San Bernardino Police Chief Jarrod Burguan said 53-year-old Cedric Anderson walked into North Park Elementary School and opened fire on his wife, Karen Elaine Smith, also 53, shortly before 10:30 a.m. local time before taking his own life.

Two students were wounded in the shooting. One of them, identified as 8-year-old Jonathan Martinez, was later pronounced dead at a local hospital. The other injured student, aged 9, was in stable condition.

Burguan said both students were standing behind Smith when the shooting began, but he does not believe they were targeted. The chief said Anderson had a criminal record, including weapons and domestic violence charges, but said he had no specifics.

The chief said Anderson and Smith had only been married for a few months and had been estranged for at least a month.

"No one has come forward to say they saw this coming," Burguan said.

A post on what appeared to be Karen Smith's Facebook page invited friends to the couple's wedding in January. The following month, Anderson posted a 12-second video in which he said Smith was "making me really happy" and "knows when to ignore me."

"That makes a happy marriage," Anderson added. 

San Bernardino City Unified School District superintendent Dale Marsden said Anderson was "known to staff" at the school and told workers that he had come to drop something off for his wife before the shooting.

The 600 other students at the school were bused to safety at California State University's San Bernardino campus, several miles away. Television news footage showed students, escorted by police officers, walking off campus hand-in-hand.

As word of the shooting spread, panicked parents raced to the school, some in tears, some praying as they anxiously sought information about their children. They were told to go to a nearby high school where they would be reunited.

Four hours later, the children began to arrive at the high school, getting hugs from emotional parents. As the students got off the buses, many of them carrying glow sticks they had been given to pass the time with, police officers applauded and high-fived them.

When the buses first pulled away, some parents ran alongside, waving and trying to recognize their children inside. Many said their children were too young to have cellphones. Others said the phones rang unanswered.

Among those waiting anxiously at the high school for her 9-year-old granddaughter's return was Alberta Terrell, who said she cried with relief when she was told that a family friend saw the girl getting safely onto a bus.

"I was really elated. But I won't be truly happy until I see her and can give her a big hug," Terrell said as she sat in the bleachers near Cajon High School's baseball diamond.

"It's frustrating for us as parents but also understandable," Holly Penalber said of the long wait, which most parents seemed resigned to.

Penalber's 9-year-old son and 7-year-old daughter attend the school. She called Monday's shootings "every parent's worst nightmare."

San Bernardino, a city of 216,000 people about 60 miles east of Los Angeles, was the site of a December 2015 terror attack that killed 14 people and wounded 22 others at a meeting of San Bernardino County employees. Husband-and-wife shooters Syed Rizwan Farook and Tashfeen Malik were later killed in a gunbattle with authorities.

Monday's shooting was the latest tragedy for a city that has struggled in recent years with more than its share of them. Once a major rail hub and citrus producer, San Bernardino filed for bankruptcy in 2012 after struggling to pay its employees despite steep cuts to the budget.

An outlying suburb of Los Angeles, it was hit hard when the Great Recession sent housing prices tumbling. As the city struggled with economic problems that forced layoffs of police and other government workers, violent crimes, particularly homicide, began to rise.

In the past year, however, the city seemed to be making a recovery. Burguan, who won national praise for the way his department responded to the 2015 shootings, announced last year he was hiring additional officers.

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The Associated Press contributed to this report.contributed to this report.