(CNN) -- A staff member at an elementary school in Knoxville, Tennessee, was taken into custody Wednesday minutes after the principal and assistant principal were shot and wounded while in the school, police said.
"We're happy that he's in custody and we're confident that he was the only one involved," Police Chief Sterling Owen told reporters.
Police were called at 12:49 p.m. and "at 1:03 we had him in custody," said Owen, who would not identify the suspect until he is charged.
The victims, principal Elise Luna and assistant principal Amy Brace, were taken to the University of Tennessee Medical Center. "One is in surgery, and the other has been treated," Owen said. "We feel like, at this point in time, both of them have a good chance of surviving."
The suspect drove away after the shooting but got caught in a roadblock for a construction project, Owen said. "He apparently surrendered at that time," he said.
As a school employee, the suspect was authorized to be in the building at the time of the shootings, Owen said.
A gun has been recovered, he added.
The students had been dismissed at 11:45 a.m., said Knoxville School Superintendent James McIntyre. All but two of the students had been picked up at the time of the shootings, he said.