(CBS) SPRING, Texas -- Three students are being held in connection with a stabbing early Wednesday at a suburban Houston high school that left one dead and three injured, officials said at a press conference.
The four victims and the three persons of interest are all students at Spring High School, where the stabbing was reported around 7 a.m. Wednesday.
"We do believe the persons of interest we have in custody are the only persons of interest we need to have in custody," Harris County Sherriff Adrian Garcia said at a press conference Wednesday.
The stabbing happened after an apparent confrontation at the school, Garcia said. The victims were injured with "some kind of cutting instrument," but police haven't recovered the weapon yet, Garcia told reporters.
The persons of interest are being questioned at the Harris County Sherriff's office, Garcia said. A news helicopter captured images of two men being led away from the school in handcuffs, CBS affiliate KHOU reported.
The 17-year-old student who died was stabbed to death, reports the station.
Two people were transported to the hospital with minor injuries, Garcia said. Another victim, a 16-year-old boy, was flown by Life Flight to Memorial Hermann Hospital, reports the station. Hospital officials reportedly said the boy is in critical condition, and his parents and pastor told reporters that he is expected to survive, but will need surgery.
Garcia couldn't confirm reports that the incident was gang-related.
As of 11 a.m. a lockdown continued, and hundreds of parents were being kept away from the campus, KHOU reported. The students were expected to be released from the back of the school by noon, said Ralph Draper, superintendent of the Spring Independent School District, which includes the high school.
"Every parent sends their children to school believing school should be one of the safe haven places they can send them and receive them at the end of the day," Draper told reporters. "In my 30-year career, this is the one things you pray never to experience."
In the aftermath of the stabbing, "our aim was to re-establish a safe and secure place for all of the nearly 3,000 students who remained on campus," Draper said.
"Priority number one was to make sure nobody else was hurt," he said.