Illinois State Police said the driver who plowed into a building housing an after-school program in downstate Chatham, Illinois, that killed three children and one teenager, was not intoxicated at the time of the crash.

The driver of the vehicle involved in the crash that killed three children and a teenager may have had a medical emergency, according to law enforcment officials.

Illinois State Police Director Brenden Kelly said early evidence from a deadly crash at a Chatham after-school program Monday indicates the driver may have suffered a medical event. But he said that is not yet conclusive. No charges have been filed, and the investigation is ongoing.