What you do when confronted with an active shooter could help save your life and the life of your family.
Law enforcement says preparing yourself for these tragedies could mean survival.
The first thing to do is run - do anything you can to get away from where the shooter is. If you can help others run and spread the word of an active shooter, then do so.
The U.S. Department of Homeland Security says if you can't run, you should hide. Hide in rooms where you can lock a door, or stack things in front of the door.
And if you can't hide - fight. If you're with a group of people, band together to fight back. Make noise, find things to throw at the shooter and yell.
Michigan State Police are urging people to speak up and say something if they ever hear something out of the ordinary.
"I think a lot of times as we go through these individual cases of shootings and any crime, you see certain points in that history where if somebody would have said something, it probably would have been prevented," said MSP Lt. Mike Shaw.
DHS says that you should raise your hands and spread your fingers so police on scene know that you're not the threat.