MCKINNEY, Texas -- Police are investigating what caused a young woman to drive erratically before crashing into a school bus full of students late Thursday night, killing her instantly.

Officers were called about an erratic Jeep Wrangler at about 11:30 p.m. As police looked for the vehicle, they were called about a crash involving a Denton ISD school bus near West University Drive and Wisteria Way.

The driver of the Jeep, later identified as Caitlyn Haynes, 22, was pronounced dead at the scene.

Students on the bus were coming back from a tennis tournament. The bus driver and students weren't injured.

It took police about three hours to remove the Jeep from under the school bus.