Two adults are dead after a shooting Monday afternoon inside Mark Twain Elementary School on Chicago’s Southwest Side, authorities said. The shooting happened around 3:40 PM at the school in the 5100 block of South Lotus Avenue. Chicago police said officers found two adults unresponsive inside the building.

A 48-year-old woman who had been shot once in the head was taken to Christ Hospital in critical condition. A 63-year-old man, who had also been shot once in the head, was taken to the same hospital in critical condition. Both were later pronounced dead.

A weapon was recovered at the school, according to police.

Authorities have not said what led to the shooting or whether the two people knew each other. Their identities have not been released.

The school was not in session when the shooting occurred. Students are scheduled to return on Aug. 24.

Earlier reports indicated that the incident involved two custodians at the school, with a male custodian reportedly shooting a female custodian before shooting himself. However, authorities have not publicly provided additional details about the circumstances or motive.

Police and Chicago Fire Department crews responded to the scene, while officers continued securing the area.