Roswell Shooting Update: Shooter Identified, Police Say He Modified Gun Before Attack

Police said the 12-year-old boy who open fired at his middle school in Roswell, New Mexico had modified the gun and coordinated the attack in advance, the Chicago Tribune reported Wednesday.

The boy fired rounds from a shotgun inside the gym at Berrendo Middle School on Tuesday. An 11-year-old boy and a 13-year-old girl were critically wounded and taken to University Medical Center in Texas. As of Thursday, the 11-year old is reported to be in critical condition, while the girl's condition is satisfactory.

There's no official motive, but police say the shooter, who is reportedly Mason Campbell, possibly warned his friends about what he was planning to do.

"We did find evidence that the suspect had planned this event," Pete Kassetas, New Mexico police chief, told the Chicago Tribune.

Police said Campbell retrieved the gun, a 20-gauge shotgun, from his house. He then modified it, and loaded it with three rounds of birdshot. Campbell then entered his school gym with the firearm hidden in a bag, the Chicago Tribune reported.

The shooting lasted 10 seconds, during which Campbell fired all three rounds, one into the ceiling, another into the floor, and one into the stands where the students were. The attack ended when one teacher, John Masterson, convinced Campbell to lower his weapon.

"For all of the anguish that many suffered," Campbell's parents and grandparents said in a Wednesday statement, CNN reported, "our family offers our heartfelt condolences and remorse in words that we cannot fully express."

Campbell was arrested but police said they are going through all of the evidence before he is officially charged. The boy, who will undergo a mental health evaluation, will most likely be charged with three counts of aggravated battery, CNN reported. According to New Mexico state law, Campbell cannot be tried as an adult because he is under the age of 14.

"As a family we will cooperate in all ways with law enforcement to piece together how this awful tragedy occurred," Campbell's family said in their statement, CNN reported.