ISABELLA TOWNSHIP, Mich. (AP) — Authorities say two people died after the car they were riding in crashed into the back of a stopped school bus in mid-Michigan.

The Isabella County sheriff’s department says the bus stopped Friday morning in Isabella Township, near Mount Pleasant, to pick up the first child on its route when it was hit. The car’s driver and a front-seat passenger were pronounced dead at the scene.

The bus driver wasn’t injured and no one else was on the bus. Names of the dead weren’t immediately released.

The cause of the crash is under investigation. Sheriff Michael Main says the early-morning sun may have been a factor since the car and bus were heading eastbound.