Slain Nev. Teacher a Former Marine

Mike Landsberry has been identified as the teacher killed by a 12-year-old student at Sparks Middle School near Reno, Nev., reports CNN . Landsberry, 45, was a popular math teacher who had served in the Marine Corps and was a member of the Nevada Air National Guard.

It appears he was attempting to reason with the shooter when he was shot and killed. Two Facebook pages memorializing the teacher have drawn thousands of likes.

Authorities have not released the identity of the suspected shooter, a minor. But he is said to have been a 12-year-old who brought his family's semiautomatic pistol to school. He took his own life. His motives are not clear, but some students have reported that he was being bullied at school, according to NBC News .

The two 12-year-old boys who were shot sustained injuries to the stomach and shoulder, respectively. Both were hospitalized in stable condition Monday, after being upgraded from critical condition. Sparks Middle School will be closed for the rest of the week.

A high-ranking homeland security official speaking at the International Association of Chiefs of Police (IACP) Conference Tuesday said police responding to mass shooting attacks must "foster a more coordinated response" to such attacks.

"We must continue to enhance our information-sharing architecture," said Rand Beers, acting director of the U.S. Department of Homeland Security.