By Lateef Mungin and Greg Botelho
New Mexico's Berrendo Middle School reopens today, even though many who return have no idea why a preteen may have taken a shotgun to the school and randomly shot at them.
And teachers have the task Thursday of helping youngsters make sense of a shooting they themselves may not understand.
"Our teachers tomorrow have a very, very difficult and stressful day coming," Roswell Superintendent Tom Burris said at a news conference Wednesday. "Tomorrow, they will all be counselors. Every staff member is in there, working to prepare the kids for tomorrow."
Police were still investigating the shooting that left two students seriously injured and the suspected shooter in custody, New Mexico State Police Chief Pete Kassetas said.
Three shells and a plan
Police say the 12-year-old suspect entered his middle school Tuesday morning with a 20-gauge pump shotgun -- which he had sawed off -- and he had three shells and a plan.
The first shot, which Kassetas characterized as "birdshot," or small pellets, hit the ceiling. The second went into the gym floor. The third sped toward the stands where, about 12 to 15 feet away, it hit two students who had been waiting with others for classes to start.
"The victims were random," the state police chief said.
Police have carried out three search warrants and interviewed more than 60 people, Kassetas said.
"We did find evidence that the suspect had planned this event," Kassetas said. "I can't discuss the particulars as to why."
The boy faces three counts of aggravated battery, according to New Mexico state juvenile court documents obtained by CNN affiliate KOAT.
The suspect's parents, Jim and Jennifer Campbell, and grandparents, Robert and Nancy Bowles, issued a statement Wednesday saying they are "praying that God will be with everyone who has been affected." The family singled out the two hospitalized victims.
They didn't try to explain the shooter's actions, which left "his whole family ... heartbroken," though they didn't ignore his impact.
"For all of the anguish that many suffered yesterday," his parents and grandparents said, "our family offers our heartfelt condolences and remorse in words that we cannot fully express."
Victims still recovering
One of the students shot was 13-year-old Kendal Sanders, who Gov. Susana Martinez said suffered injuries to her right shoulder.
Doctors at University Medical Center in Lubbock, Texas -- about 175 miles east of the school -- upgraded her to stable condition Tuesday night. Kendal is likely to remain hospitalized for a week or more, the governor said.
The other victim, who is 12 and whom officials aren't naming because of a request from his family, was in critical condition with injuries to the side of his face and neck, Martinez said. This boy has undergone at least two surgeries since the incident.
"He is in worse condition than Kendal," the governor said Wednesday afternoon.
Police: Suspect took parents' gun
The suspect is being held at an unspecified location in Albuquerque and has met with his parents, Kassetas said.
In their statement, the parents indicated a judge "ordered ... our son receive an evaluation and mental health treatment and sincerely want him to receive all of the help that he needs."
"As a family we will cooperate in all ways with law enforcement to piece together how this awful tragedy occurred," they said.
Kassetas said the shotgun came from the suspect's home. His father had bought the gun -- the only one of several weapons in the house not locked in a safe -- at a Walmart, according to a law enforcement source with knowledge of the investigation.
Authorities believe the 12-year-old "modified the weapon by cutting off the stock," Kassetas said.
The search warrants executed in connection with the investigation were on the suspect's locker, his duffel bag and his Roswell home.
The law enforcement source said the suspect kept a handwritten journal at home describing "what he was planning, what he wanted to do."
But just before he fired, authorities believe, the suspect gave "preliminary warnings ... to some select students who he ran into before he entered the gymnasium," Kassetas said.
Teacher John Masterson didn't know the shooter had used all his ammunition when he walked to the student and persuaded him to put the gun down, Martinez said.
"Mr. Masterson ... was a hero ... who stood there and allowed a gun to be pointed right at him," the governor said at a vigil Tuesday evening, "and to talk down that young boy to drop the gun so that there would be no more young kids hurt."
The Berrendo staff directory lists John Masterson as an eighth-grade social studies teacher.
Masterson has taught at the school for a decade and coaches track and soccer, according to the Albuquerque Journal.
When contacted by the newspaper, he said police had told him not to discuss details of the shooting.
"It was a harrowing experience," he told the paper. "All I can say was the staff there did a great job."
CNN's Susan Candiotti, Chuck Johnston and Vanessa Juarez contributed to this report.
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