VIRGINIA BEACH, Va. (WVEC) -- Salem High School went on lockdown Thursday morning, after one of its students died on campus.

A Virginia Beach Public Schools spokesperson said the initial call to police was about someone possibly in cardiac arrest around 8 a.m.

Coincidentally, it was parents day at Salem High School, a way for students to show their parents what an average day was like for a high school student.

For parent Demone Smith, Thursday was anything but average. Smith was inside the school when an announcement came over the loudspeaker that the school was on lockdown.

"The whole mood changed," said Smith. "The teacher locked the door, turned off the lights, put all the children on one side of the classroom away from the door."

Parent Danielle Lumbgoodrum said she started thinking the worst after sitting in the dark with her child, without hearing any news.

"The next thing you're thinking is are we going to make it out alive?" asked Lumbgoodrum. "If someone comes through and they have a gun, how are we going to protect 40 kids?"

A message was emailed to parents by the principal said there was a medical issue involving a student, and that there was no reason for parents to pick up their children.

A second email from Principal Matt Delaney confirmed a student had passed away:

Good morning, Salem High School parents.
This is Principal Matt Delaney calling with an update to today’s external lockdown. I want to let you know that police are investigating the death of an individual student at our school. Officers tell us that no foul play is suspected and police are not looking for a suspect. While the external lockdown continues, we are making plans for an early departure for all students by 12:00 p.m. today. Students will be offered a bag lunch as they exit the building. Bus transportation will be provided and dismissal will occur as usual. There is no need for parents to pick their children up at the school, unless this is your typical practice. In addition, all afterschool activities here at Salem High School are cancelled today. I appreciate your continued patience and understanding. This is a sad day for our Salem community. Please know that counselors are at the school now and will continue to be available in the days ahead. Thank you.

Superintendent of Schools Aaron Spence said the school went on lockdown due to the student's medical emergency. 13NewsNow asked if the school thought the student body was in danger at the time the lockdown was issued.

"No, again, the lockdown this morning was because we had an ongoing police investigation around an individual student," said Spence.

Virginia Beach Police say no foul play is suspected, and they are not looking for suspects.

This is a developing story. Stay with 13News Now for more details.