ELNORA, Ind. (AP) — Authorities say two children and two adults have died in a crash after the driver failed to yield at a stop sign in southwestern Indiana.

Daviess County Chief Deputy Steve Sturgis says Matthew Grimes of Evansville pulled out in the path of a westbound F-150 about 6:30 p.m. Thursday. Sturgis says, “We know what happened but we don’t know the why.”

The victims were Grimes and his 5-year-old daughter, Maddalynn. Jessica Krohn of Evansville was also killed, along with 7-year-old Isabella Pfingston.

The crash occurred about 80 miles (129 kilometers) southwest of Indianapolis. The driver of the pickup truck had a head injury. Investigators don’t believe alcohol or drugs played a role, although more tests are pending.