BUTTE, Mont. -

Authorities in Silver Bow County released the name of the woman struck and killed walking on Interstate 15 Tuesday night.

Investigators say 61-year-old Peggy Joyce Witt had gotten out of a car near the Buxton exit,  about 10 miles south of Butte.

The woman was walking along the northbound lanes when she was hit by a passing vehicle.

Several folks reportedly called to report a woman walking dangerously close to traffic.

According to officials the final call came in around a quarter after six and that’s when the caller informed police the woman had been hit.

Investigators say the unknown driver immediately fled the scene but they were able to collect parts from the vehicle that had broken off on contact.

"The vehicle that struck her left the scene.  We're unsure right now what the type of vehicle it was.  We do have parts from that vehicle that we're going to try and identify the type of the vehicle based on the type of evidence that was left there," said Gary Becker, Captain for the Montana Highway Patrol.

Police saw another pair of tire tracks from a different vehicle, one they believe stopped after the woman was struck and then left without calling the authorities.

If anyone has any information relating to this incident, investigators are asking you to call the Montana Highway Patrol at 494-3233 or Crime Stoppers at (406) 497-1120.