The rape and murder of Lisa Kimmell, aka "Lil Miss," was one of the most shocking and brutal crimes of its era -- the subject of multiple television shows and a book written by her mom that traces heartbreak over the course of more than a decade.

The killer of Denver-based Kimmell, Dale Eaton, is on death row in Wyoming, but his attorneys continue to fight for his life. Now, a Colorado psychiatrist speaking at a hearing looking into claims of inadequate defense says he may suffer from bipolar disorder.

The Murder of Lil Miss by Sheila Kimmel describes how Lisa, a manager at a local Arby's restaurant, left her Denver home for Billings, Montana, where she planned to visit some friends. She drove a Honda with a personalized license plate reading "LIL MISS."

But she never reached her destination, prompting a frantic search that ended in the worst conceivable way. Here's an excerpt from the book:

Eight days after her disappearance, our worst nightmare materialized. Two fisherman found Lisa's body early Saturday afternoon, April 2nd, 1988. She hadn't had a wreck. At the tender age of eighteen, Lisa had been raped repeatedly, held hostage for six days in an old school bus without electricity or running water, subjected to untold torture, hit on the head so hard that it caused a four-inch skull fracture, and stabbed six times. Her body had been dropped from the Old Government Bridge near Casper, Wyoming, into the cold North Platte River. Our beautiful daughter was gone.

Within weeks, Lisa's story was featured on the TV program Unsolved Mysteries (A&E's Cold Case Files also highlighted it), and over the months that followed, a number of clues surfaced, with arguably the strangest being a note left on her grave that October. It read:

Lisa --

There are'nt (sic) words to say how much you're missed the pain never leaves it's so hard without you you'll always be alive in me. Your death is my painful loss but Heaven's sweet gain.

Love always, Stringfellow Hawke

By the way, Stringfellow Hawke was a character played by actor Jan Michael Vincent on the network series Airwolf.

Years later, the handwriting on the note was matched to Eaton's -- but that wasn't the key to breaking the case.

Continue for more about the Dale Eaton hearing and Lisa Kimmel's murder, including additional photos. Instead, as reported by 7News, which has done a fine job of covering the case since the beginning, DNA found at the scene scored a hit with Eaton's in 2002.

At the time, Eaton, a welder and ex-felon, was in a Colorado prison after being caught with a firearm; he was also facing an involuntary-manslaughter beef related to the death of a fellow prisoner. As such, he wasn't on hand when authorities searched his property, near the Wyoming community of Moneta. Honda parts found there led to a more thorough search and an even more startling find: Lisa's car had actually been buried, along with part of her "LIL MISS" license plate.

Nearly two years later, a jury found Eaton guilty of first-degree murder and multiple kidnapping and sexual assault offenses. He was sentenced to death in March 2004 -- and the following month, the Kimmels were awarded $5 million in a wrongful death lawsuit.

But before long, a new legal team began arguing that Eaton's defense had been flawed. Their efforts led to a 2012 filing in which they criticized the performance of his original attorney. Also faulted were prosecutors, for allegedly failing to reveal that an inmate who testified against Eaton -- he'd allegedly told the man he'd kidnapped Kimmel at gunpoint when she stopped to use a rest-stop bathroom -- "was in line to receive a lower prison sentence," 7News reported last year.

These efforts have led to what the station calls an ongoing "multi-week hearing" about the Eaton crew's complaints. As part of the session, Windsor-based psychiatrist Dr. Kenneth Ash suggested that Eaton suffers from bipolar II disorder, a mental illness associated with major depression and hypomania.

It's too early to know if this revelation will have an impact on Eaton's sentence. But already, it's clear that the case is following the trajectory of virtually all death-penalty convictions -- many years of court challenges and appeals.

Nearly ten years after Eaton was sentenced, and a quarter century since the original crime was committed, there's no end in sight.

Here's a look at another Eaton mug shot.

More from our Colorado Crimes archive: "Francisco Carbajal busted in cold-case strangulation of Julia Abarca."

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