A death row inmate is due to be executed on the state of Texas' sixth try - including one failed attempt where he was just minutes from death.
Larry Swearingen was convicted of abducting, raping and strangling 19-year-old college student Melissa Trotter in December 1998.
He has denied murdering the teen and claims they were "friends with benefits".
Barring a last-minute stay, the 48-year-old will be strapped to a gurney and injected with a cocktail of lethal drugs in Texas' execution chamber on Wednesday night.
Miss Trotter's grieving family are eager for the lethal injection to be carried out as Swearingen's supporters and capital punishment opponents fear an innocent man is being sent to his death.
Recalling the scheduled execution that was called off with just minutes to spare, Swearingen told Texas Public Radio (TPR): “When you're sitting there watching the clock, it really speeds up a lot faster."
His legal team has filed last-minute appeals to block the execution.
For Miss Trotter's mum, Sandy, now a grandmother, it will be the sixth time she has prepared herself to watch Swearingen die.
She will look on from a witness room at the state prison in Huntsville, along with Miss Trotter's 92-year-old grandfather and other family members.
She told TPR she had no doubt Swearingen is her daughter's killer, adding: “We are more than ready to be done so hopefully it’s looking more likely it’s going to happen.
“It's been very frustrating for our family and horrific for the 92-year-old grandfather Charles Trotter Senior. He will be there viewing Swearingen executed."
Miss Trotter vanished in the city of Willis in December 1998, sparking a search that ended in heartbreak the following month, in January 1999, when hunters found her partially-naked body in the Sam Houston National Forest north of Houston.
Prosecutors said she was strangled with her own pantyhose.
She was last seen alive at a student centre at Lone Star College.
Swearingen, an electrician then aged 27, immediately came under suspicion because he and Miss Trotter were seen together at the college the day she disappeared.
He was arrested on traffic warrants three days later and has been locked up ever since, TPR reported.
Swearingen initially denied knowing Miss Trotter, but she had his pager number and strands of her hair were found in the stolen truck he had been driving.
Swearingen has maintained his innocence and cast doubts on the "mountain" of circumstantial evidence that prosecutors used to convict him and send him to the execution chamber.
Prosecutors said the torn leg of pantyhose used to strangle Miss Trotter was found inside Swearingen's caravan - calling it "smoking gun" evidence - and polyester fibers from his truck were found on her coat.
The segment of pantyhose was allegedly found by Swearingen’s landlord in a bag of rubbish while he was cleaning the caravan before new tenants moved in.
A mobile phone tower "ping" put him close to the spot where Miss Trotter's body was found, prosecutors claim.
The brand of cigarettes smoked by Miss Trotter were allegedly found inside his home, even though he and his wife did not smoke.
And after Miss Trotter disappeared he falsely reported a burglary that left his home ransacked, according to prosecutors.
Swearingen claims investigators relied on "junk science" and forensic techniques that were flawed.
He has argued that "legitimate" forensic science found that he was in jail when the teen was murdered and the pantyhose allegedly found in his home was not the murder weapon.
Experts for the defence claim blood found under Miss Trotter's fingernails did not match Swearingen's DNA and she had been dead for two weeks when her body was found - a period of time when Swearingen was in jail.
Before he was convicted, he wrote an anonymous letter in poor Spanish and sent it to authorities in a desperate bid to exonerate himself.
The letter contained unreported details about the victim's underwear and body, and claimed Swearingen was innocent, but authorities later found out he wrote it.
His supporters include death penalty opponent Sister Helen Prejean, who inspired the film Dead Man Walking and was portrayed by Susan Sarandon on screen.
She tweeted: "Multiple forensic experts now say that evidence presented at Larry’s trial doesn’t actually hold up under scientific scrutiny and that expert testimony at the trial was 'overstated.'
"Two different fiber analysis experts examined the pantyhose materials after the trial and they concluded that the pantyhose found by Larry’s landlord and the pantyhose used to kill Melissa did NOT match.
"A third fiber analysis expert says that the state lab technician’s testimony at Larry’s trial was 'overstated.' That’s been confirmed by the Texas Department of Public Safety. They now say that the technician should NOT have testified that all other pantyhose were excluded."
But as far as prosecutors, police and Miss Trotter's family are concerned, the evidence against Swearingen is "overwhelming" and he is the killer.
Swearingen's bid for clemency was denied on Monday in a 7-0 denial by the Texas Board of Pardons and Paroles, the Houston Chronicle reported.
Afterwards, prosecutor Kelly Blackburn said: “We appreciate the parole board’s careful review of the true facts of this case and are now one step closer to the long-awaited justice which Melissa Trotter and her family deserve.”
Swearingen's supporters held a protest outside the Montgomery County Courthouse on Tuesday.
This is the sixth time he has been scheduled for execution in the past two decades. Previous dates were postponed due to court appeals.
Swearingen is set to be the third prisoner to be executed in Texas and the 12th in the US in 2019.
