Foul play is not suspected, sheriff’s Lt. Robert Westphal said.
A janitor saw the man at Baldwin Academy, 1616 Griffith Ave., and called the station at 8:51 a.m., sheriff’s Lt. James Long said. Deputies found him with a gunshot wound to the head and unresponsive.
Paramedics pronounced him dead at the scene.
When the man was found, Long estimated there were five children of employees at the school. Hacienda La Puente Unified School District students are on distance learning. It was unclear when the fatal bullet was fired.
Investigators believe the same man was seen shooting into the air around 10 p.m. Sunday on Francisquito and Mullender avenues in Valinda, Westphal said. Five to six shots were heard.
Deputies looked for the shooter Sunday night but didn’t find him, Long said. That location is less than a half-mile from the school.