American mass shootings tend to have a grim pattern: A man opens fire with a school or workplace, claiming lives and sowing chaos.
But the shooting at YouTube headquarters in California on Tuesday afternoon appeared different in at least one respect: The suspected shooter would be a woman. The suspect, who had previously been in their 30s, opened fire while on an outdoor kitchen at lunchtime, motivated by what authorities believe was a domestic dispute, multiple senior law enforcement officials told NBC News. She died of an gunshot wound.
It’s uncommon for any mass shooter to be female: There were only three cases in the past 30 years, as outlined by a database provided by Mother Jones. And research conducted with the New York Police Department found that only eight of 230 “active shooter” cases inside United States from 1966 to 2012 involved female attackers.
And inside broader category of mass killings, including other methods of execution, like arson, only 6 percent of perpetrators are women, according to a database published by USA Today.
“It’s definitely rare to view a lady shooter,” said Sherry Hamby, research professor of psychology in the University in the South. “The more extreme the violence, a lot more likely the perpetrator is being male.”
Hamby said reports have pointed to a selection of reasons males are more likely being violent, including a feeling of entitlement. When women are violent, there tends being an association with a domestic dispute, Hamby said.
Mother Jones used a strict list of criteria for his or her mass shooting database. They looked over incidents where at least four people, not including the shooter, were killed, knowning that took place in the public place (not a private residence), usually inside a single location.
Out of 73 incidents that met that criteria, just three public mass shootings since 1982, such as the San Bernardino attack in 2015, involved a female killer.
As of Tuesday afternoon, authorities have never confirmed any deaths inside YouTube shooting, so the suspect wouldn’t fulfill the Mother Jones database’s criteria for any mass shooter.
San Bernardino shooting
Tashfeen Malik, 27, and her husband, Syed Rizwan Farook, 28, unleashed a hail of bullets on a conference room at the Inland Regional Center, a state-run facility for people with development disabilities, on Dec. 2, 2015, killing 14 people. The pair were slain about four hours later in a shootout with police.
Alturas tribal shooting
Cherie Lash Rhoades, 44, former chairwoman of the Cedarville Rancheria tribe, opened fire at the Cedarville Rancheria Tribal Office and Community Center in Alturas, California on Feb. 20, 2014. Among those killed were her brother, her niece, and her nephew. When she ran out of ammunition, she grabbed a butcher knife and stabbed another person. All told, she killed four people and wounded two.
The Goleta postal shooting
Jennifer San Marco, 44, a former postal worker, fatally shot a former neighbor in Goleta, California, then drove to the mail processing plant where she used to work on Jan. 30, 2006. She opened fire inside, killing six employees before killing herself. The U.S. Postal Service said that San Marco worked for the Postal Service for six years, but was given early retirement in June 2003 because of psychological problems.