May 22 (UPI) -- Galveston County Sheriff Henry Trochesset has given more details about the timeline of last week's shooting attack at Santa Fe High School near Houston.
During a news conference Monday, the sheriff said school resource officers had confronted shooter Dimitrios Pagourtzis, a 17-year-old student who confessed to Friday's assault that killed 10 and injured 13.
By the end of the attack, Pagourtzis became trapped in a room by police, Trochesset said.
"They're heroes," he added. "They contained him in that one area ... so he did no more damage to other classes."
The sheriff said 200 officers rushed to assist school district police.
Trochesset, who didn't specify how resource officers responded so quickly, said he doesn't believe law enforcement crossfire hit any victims. But he said that won't be known for sure until autopsy reports are finished.
School district officer John Barnes was shot in the arm, and hospitalized in critical condition with severe blood loss. He underwent an eight-hour surgery at a University of Texas Medical Branch Hospital in Galveston.
Charged with capital murder, Pagourtzis has been held in solitary confinement on suicide watch, officials said. Officials said a shotgun and .38-caliber revolver found at the scene were legally owned by his father.
Defense attorney Nick Poehl told ABC News his client had been bullied by students and adults at Santa Fe High School.
School officials said they investigated the bullying claims and concluded they were untrue.