SAN BERNARDINO (California) • A gunman opened fire in a California school classroom, killing a teacher and an eight-year-old boy before turning the gun on himself.
A second child was badly hurt by the gunman, who is said by the authorities to have had a criminal history that included weapons charges and domestic violence that predated his brief marriage to the slain teacher.
Police said local resident Cedric Anderson, 53, checked into the school office on Monday as a visitor - to "drop something off with his wife" - after entering the campus in the city of San Bernardino and going to a classroom, where he opened fire on Ms Karen Elaine Smith, 53, as she was teaching.
Officers said Anderson had targeted only Ms Smith, but two pupils were caught in the crossfire and one of them, Jonathan Martinez, died later in hospital.
"This does appear to have been a murder-suicide... with the male succumbing to a self-inflicted gunshot wound," said Lieutenant Mike Madden of the San Bernardino Police Department.
Pupils at North Park Elementary School - which has around 500 children between kindergarten and sixth grade - were transported to a nearby campus, where they were "being well cared for, having snacks, playing games and watching a Disney movie", the police said.
San Bernardino, about an hour's drive east of Los Angeles, was the scene of horrific violence when Syed Rizwan Farook and his wife Tashfeen Malik gunned down 14 people and wounded 22 others in December 2015 before being shot dead by police.
Monday's shooting could reignite the debate on gun violence in the United States, where attempts to put in place tougher gun control measures have failed, despite a series of mass killings.
In one of the most notorious school shootings in the country's modern history, 20 children and six staff members were massacred in 2012 at Sandy Hook school in Newtown, Connecticut.
The US has had an average of 52 school shooting incidents a year since the Sandy Hook tragedy, according to Everytown for Gun Safety, a gun-control group.
Total school shootings, a figure that includes elementary and high schools as well as colleges, regardless of whether anyone was killed or wounded, rose from 37 in 2013 to 58 in 2014, and to 65 in 2015, before declining to 48 last year, according to the group's data.
With Monday's incident in San Bernardino, the US has now had 12 school shootings this year, on track to match last year's tally.
Security experts said schools have few options to limit such incidents, given the prevalence of guns in the country. One possible answer, said Professor John DeCarlo, a criminal justice don at the University of New Haven, would be for schools to sweep all who enter with metal detectors like those used at airports and sports venues.
An estimated 10,000 people are murdered with guns each year in the US, according to federal crime statistics. In February, President Donald Trump signed a measure to unblock an Obama-era rule designed to keep guns out of the hands of certain mentally ill people.
With Monday's San Bernardino incident, the US has had 12 school shootings this year, on track to match last year's tally. Here are some prominent cases:
April 20, 1999, Columbine High School, Colorado: Eric Harris, 18, and Dylan Klebold, 17, killed 12 students and a teacher before committing suicide.
March 21, 2005, Red Lake, Minnesota: Jeffrey Weise, 16, killed two people at home, then shot dead five students and two staff members before committing suicide.
Oct 2, 2006, West Nickel Mines School, Pennsylvania: Charles Carl Roberts, 32, killed five girls before committing suicide.
April 16, 2007, Virginia Tech, Virginia: Cho Seung Hui, 23, killed 32 students and faculty members before committing suicide.
Feb 27, 2012, Chardon High School, Ohio: Thomas Lane, 17, killed three male students. He was arrested and convicted.
April 2, 2012, Oikos University, California: L. Goh, 43, shot dead seven students and staff. He surrendered and, in 2015, was judged incompetent to stand trial.
Dec 14, 2012, Sandy Hook School, Connecticut: Adam Lanza, 20, killed his mother, then shot 20 children and six school staff before committing suicide.
June 7, 2013, Santa Monica College, California: John Zawahri, 23, killed five people before being shot dead by police.
Oct 24, 2014, Marysville- Pilchuck High School, Washington: Student Jaylen Fryberg, 15, shot dead four students before committing suicide.
Oct 1, 2015, Umpqua Community College, Oregon: Chris Harper-Mercer, 26, killed a teacher and eight students before committing suicide.