LAS VEGAS -- A busy stretch of northbound Interstate 15 was finally opened at about 2:30 p.m. Thursday after being shut down for more than nine hours.

Traffic was being funneled down to one lane past the site of the 5:10 a.m. double fatal.

A man and a woman were killed after being struck by possibly multiple vehicles north of the Saint Rose Parkway on Interstate 15 near Silverado Ranch Boulevard.

As troopers investigated the scene, the coroner's job was more difficult.

Both victims appeared to have been dismembered, and there were body parts all over the freeway.

It was so bad that an environmental cleanup crew had to be brought in.

"The male was out changing the tire. The female could have been either flagging for help or simply trying to alert motorists that someone was changing a tire," said Nevada Highway Patrol Trooper Kevin Honea.

Troopers interviewed at least four rig drivers, including at least one that went to a nearby truck stop and was allegedly trying to dispose of evidence.

Honea said even if they conclude this was an unfortunate accident, because the driver left the scene, the driver now faces a felony hit-and-run charge.

The names and ages of the victims have not yet been released.

NHP said the male victim was carrying an Oregon ID.

Anyone with information on the crash is asked to call 702-432-5219.