DENVER -- Lisa Marie Kimmell, 18, left her job at an Arby's in Denver at 4:30 p.m. on March 25, 1988, and began driving north on Interstate 25 toward Cody, Wyo., to visit her boyfriend. It should have taken her four or five hours.

Several hours after she left Denver, a Wyoming highway patrolman stopped her for speeding on I-25 near Douglas, Wyo.

Kimmell didn't have the money to post bond for the traffic citation, so the patrolman escorted her into Douglas to make a withdrawal from an automated teller machine. When Kimmell's card didn't work, she signed a promise to appear in court.

The trooper gave her directions back to I-25. It was 9:08 p.m. and the last time anyone, but her killer, would see her alive.

Kimmell never made it to her boyfriend's home in Cody. The next day, he called authorities in Colorado and Wyoming to find out if Kimmell had been in an accident.

On March 27, Kimmell's father, Ron Kimmell, reported his daughter missing. The family mounted a personal search for her car that included flying over the highways that Kimmell might have used in Wyoming and Montana.

During the week-long search the family distributed hundreds of fliers throughout Colorado, Montana, Utah and Wyoming in an effort to locate her.

On April 2, fishermen found Kimmell's nude body in the North Platte River. The body lay in the water south of the Old Government Bridge near Casper, Wyo., approximately 60 miles from Douglas, where the trooper stopped her for speeding.

Police say Kimmell was killed by blunt trauma to her head and stab wounds to her chest, which were delivered in a distinctive pattern. She had been raped and sodomized. DNA evidence of her attacker was collected from her body.

Police found traces of Kimmell's blood on the bridge (crime scene map, left), leading them to believe that someone dumped her body into the river from the bridge.

Although Kimmell had been missing for eight days, an autopsy revealed that she had been killed shortly before her body was discovered. Police believe her attacker had held her captive for a week before killing her.

Kimmell drove a 1988 two-door black Honda CRX with a sunroof and Montana license plate with the personalized registration "LIL MISS." Neither her car nor any of her belongings were ever located, until this week.

Authorities said that Old Government Bridge was difficult to see in the dark from nearby U.S. Highway 220 and hard to locate, leading them to believe the killer might know the area.

Greg Cooper, former FBI profiler, former Provo, Utah police chief and current Chairman of the Utah criminal Tracking and Analysis Project, told APBnews.com last year that several facets of Kimmell's rape and murder pointed to a sophisticated criminal:

• The distinctive pattern of knife wounds
• The sexual assault
• Dumping the victim in the river in a possible attempt to wash away physical evidence
• The amount of control the killer had over the victim
• The complete disappearance of Kimmell's vehicle

Cooper also said there might be more than one offender.

"From my perspective, this is a serial homicide," said Cooper. "This would not be a case where you would look at this and suggest that it was a singular event, but one of a series by an individual who participates in these types of crimes over a period of time."

There have been at least three other similar cases in the area that have puzzled investigators:

In the four years prior to the Kimmell's homicide, two young women were murdered in the Casper area. One of them was a 21-year-old female who was found naked and strangled along I-25 north of Casper in 1982. She was last seen hitchhiking.

The other Casper victim was found about 14 miles south of I-25 in 1986, but was fully clothed. She had been run over about 25 feet from the roadway. She was last seen walking to a friend's house in Casper. Both cases remain open.

In 1997 a 24-year-old woman disappeared while jogging along a road in Fremont County -- the same county where the car was unearthed this week. She has never been found.

Additional Resources:

• Unsolved Murders In The Casper Area
• Wyoming Unsolved Cases