Police were called to Western Heights Middle School in the 1300 block of Marshall Street in Hagerstown at approximately 4:30 p.m. to make sure the people in a vehicle in the parking lot were OK, according to WJLA.
There was a woman in the front seat of the small silver car, with two very young children in the back, WBAL reported.
The three individuals were pronounced dead at the scene, according to the Associated Press.
Police said there were no signs of violence and the area was safe.
According to WHAG, the medical examiner was working to establish the cause and manner of death.