SPRINGFIELD, Ill. — Days after a four children under the age of 18 were struck and killed when a car crashed into an after-school camp in central Illinois, the Director of the Illinois State Police said Thursday that preliminary toxicology results for the driver of the vehicle came back negative for alcohol and controlled substances.

While no charges have been filed in connection with the crash in Chatham, Ill on Monday afternoon, ISP director Brendan Kelly said the investigation was ongoing. When complete, evidence would be presented for the Sangamon County State’s Attorney to make a charging decision.

Authorities continued to rule out the idea that the incident was part of some targeted attack and are still looking at whether it was the result of some sort of medical emergency.

The car on Monday left a road, crossed a field and smashed into the side of the building in Chatham used by Youth Needing Other Things Outdoors, also known as YNOT, according to Illinois State Police. It traveled through the building, striking people before exiting the other side. Six children were also hospitalized, including one left in critical condition.

Security camera footage showed the vehicle was “a substantial distance” away when it left the roadway, said Jamie Loftus, founder of YNOT Outdoors. After speeding across a field, it crossed a road, the sidewalk and YNOT’s parking lot before crashing through the building “with no apparent attempt to alter its direction,” Loftus said earlier this week. The vehicle then crossed a gravel road and crashed into a pole and fence.

Chatham is a community of about 15,000 people outside of the Illinois capital of Springfield.

Those killed were Rylee Britton, 18, of Springfield, Ainsley Johnson, 8, Kathryn Corley, 7, and Alma Buhnerkempe, 7. All of the children were from Chatham.