Two men, a woman, and the suspected gunman were shot and killed on Friday in a rural Pennsylvania shooting. Three state troopers were injured as well, according to NBC News.
One of the injured troopers was shot but was protected by his bulletproof vest, one was injured in a vehicle crash, and one was injured by flying glass from a bullet that was shot through his car window, according to NBC News. None of those injured sustained life-threatening injuries.
The troopers shot and killed the suspect.
The suspect started shooting at random along a rural road in the Altoona-Hollidaysburg area, according to reports. Altoona is 100 miles east of Pittsburgh.
Officials are investigating the incident.
Because it involved the killing of four or more people, the Pennsylvania incident meets the FBI criteria for a mass killing — apparently the first one since last Friday's shooting in Newtown, Conn., that left 26 dead, 20 of them elementary school children.
Mass killings occur in the United States every two weeks on average, according to a USA Today study that looked at such attacks over a five-year period and involving 774 people, including 161 young children.
"Everybody is surprised when they hear it's dozens a year," James Alan Fox, a criminologist who has mass murders at Northwestern University told the publication. "People don't understand them. When they think of mass murders, they only think it's random."
The study showed that a gunman acting alone occurs in less than half of mass killings. Notably, a third of killings didn't involve guns at all.
The Pennsylvania shooting came the same day the National Rifle Association held a press conference, breaking its silence on the Newtown school shooting. The pro-gun lobbying group's vice president, Wayne LaPierre, made the case for armed guards at schools across the U.S.
"The only thing that stops a bad guy with a gun is a good guy with a gun," LaPierre said.
© 2014 Newsmax. All rights reserved.