DENVER (KDVR) – As new details emerge about the Texas school shooting that left 21 dead, Texas law enforcement officials have revealed a school resource officer encountered the gunman outside the school. 

According to Lt. Chris Olivarez with the Texas Department of Public Safety, that officer was unable to stop the suspect from entering the school but did force him to drop a backpack filled with ammunition. 

“He prevented more casualties and more mass shootings that could have taken place,” Olivarez said. 

At Able Shepherd Readiness Training in Centennial, founder Jimmy Graham said more officers need to be stationed inside Colorado schools. 

“It is time to do this,” he said. “Without that, it’s only going to end one way.”

Graham’s organization trains people, primarily gun owners, how to deal with active shooter response. He said the client base now includes law enforcement as well as teachers.

“We say it this way: In an emergency, everyone has a role, everyone has a responsibility, not necessarily to neutralize a threat — perhaps it’s helping a child, perhaps it’s evacuating them to a safer venue. But everyone has a role, and those roles need to be practiced,” Graham said.

He also believes those officers stationed inside schools should consider carrying more than handguns. The Texas shooter reportedly had an AR-15. 

“If you look at the data of what’s being used, in law enforcement they have a thing called the force continuum, the force continuum says if somebody aggresses you here, then you go here,” he explained. “You have to be able to beat that level of force.”

The National Education Association says having guns in schools is, on balance, unsafe for kids.

Meanwhile, districts like Boulder Valley and Denver Public Schools move away from traditional school resource officers, citing studies showing students of color are disproportionately ticketed and arrested.

In Denver, 20 armed patrol officers now patrol the district, along with roughly 80 campus safety officers, who are not armed. 

The district said those 20 patrol officers are staggered throughout the district to ensure fast response times to any given school.