Funk told ABC7 News that the pool was locked up Thursday night after swim practice, before P.E. classes came in on Friday morning.
The pool is in a locked enclosure with a 15-foot fence topped by barbed wire. There's also a burglary alarm, which did not go off, according to Funk.
"All the doors were locked and the alarms didn't go off," Funk said. "That person must have gotten into the pool by climbing over the fence."
"Like the first thing going through my head, was like, 'Was it a murder? Was it an accident?' That's what I was wondering," Piedmont Hills High School senior Cesar Aribal said.
First responders say the body of an adult male was found fully clothed and weighted down. Fire officials had to use specialized urban search and rescue equipment to raise the body out of the water. Investigators are trying to determine whether this incident was intentional.
The superintendent says the school is outfitted with security cameras, and they've since turned over the video to police for processing. Many students were puzzled by what they saw, turning to technology to spread the word.
"It is very shocking, I was a little bit scared because I thought this would be a student that I knew," Piedmont Hills High School sophomore Daijon Bereola Carson said.
The Santa Clara County Coroner's Office has yet to release the man's identity, but district leaders have confirmed it was not a student or staff member, bringing some, but very little relief to this campus community.
"Condolences for the family, prayers go out to them, whoever it is," Aribal said.
Students were sent home early Friday, but not before grief counselors were brought in to comfort.
Bay City news contributed to this report.