What do you do if a gunman storms a house of worship while you're inside?
Inside Edition spoke to security expert Bill Stanton on what to do to protect yourself.
There are three options: Run, hide or fight, Stanton said.
First, run out as fast as you can, ducking to avoid any gunfire.
Second, take cover under the pews, shielding any particularly vulnerable areas, like your head.
Third, you can try to fight by disarming the suspect, Stanton said.
America's places of worship saw increased security Sunday and into Monday after a gunman attacked a synagogue in Pittsburgh Saturday morning.
Robert Bowers, 46, faces dozens of charges for opening fire at the Tree of Life Congregation, killing 11 people. According to the criminal complaint against him, Bowers allegedly told a SWAT officer he "wanted all Jews to die."
The massacre is just the latest to unfold at a house of worship. Last year, 26 people were killed after Devin Patrick Kelley opened fire at a church in Sutherland Springs, Texas. Kelley later died while fleeing the scene of the crime.
And in 2015, Dylann Roof, 24, killed nine parishioners at the Emanuel AME Church in Charleston, South Carolina. He was sentenced to nine consecutive life sentences without parole in 2017.