he stretch of Emory Road in Harriman where Elishea Gilreath was fatally struck by a driver on January 18th, 2010

HARRIMAN, (Tenn.) --- Harriman Police are calling it a hit and run.

But the family of Elishea Gilreath, 33, worries it could be more.

"I want answers," Gilreath's cousin, Cindy Phillips, told Volunteer TV Thursday.

"I have to try and block it from my mind. It's hard for me to go to sleep," she said.

Gilreath was walking along Emory Drive around 6:30 pm Monday, when police say she was struck by a hit-and-run driver.

"At this point this has been classified as a hit-and-run," Detective Jason Joseph said.

The impact was strong enough to knock Gilreath completely out of her shoes, he said.

Her purse contents were also scattered across the road.

Investigators believe Gilreath and her boyfriend had argued in a car, and he dropped her off at Riverfront Park.

Police say she was walking home when she got hit and tossed into a 15-foot ditch.

"Her body wasn't visible to anyone walking or driving by," Joseph said.

An anonymous tipster called Harriman Police from a pay phone and led officers to her body around 9:30 Tuesday morning.

The male caller wouldn't give his name, authorities said.

"For them not to give their name, that's bugging me," Phillips said. "Why would you refuse to give your name, if there wasn't something that you don't want told."

Phillips begged the driver to call police and relieve her agony.

"If you didn't see her and you hit her, just tell them," Phillips urged. "Don't let us think that somebody intentionally hit her and just left her. That's a terrible feeling."

Autopsy results released Thursday showed Gilreath died almost instantaneously, authorities said.

"That's a relief because in the back of your mind, you're thinking, 'Did she lay there? Was she crying'," Phillips said.

Phillips must now decide how she'll explain what happened to Gilreath's three-youngest children.

Phillips says she got custody of the kids after Gilreath started using drugs.

"She was a good person. She'd made some mistakes. Nobody is perfect," Phillips said.

The youngest child is just two months old.

"That's going to be a hard thing," Phillips said. "I'll put pictures of her in their life books so they will know what their mother looked like."

Phillips said Gilreath's two-oldest children live with other family members.

Police say they've interviewed Gilreath's boyfriend. Investigators said he's not a suspect, and his truck showed no damage.

Police think the vehicle that struck Gilreath was a 2001 to 2005 silver Ford Ranger. The front passenger side would have sustained damage.

If you have any information that could help investigators, call police at (865) 882-3383.