"I did not murder my children. I had nothing to do with this," says Darlie, proclaiming her innocence.
The state decided to try Darlie for the murder of 5-year-old Damon. Because of his age, that killing was a capital offense in Texas, punishable by death.
To bolster its circumstantial case and provide a motive for the killings, prosecutors Greg Davis and Toby Shook focused on Darlie's character. They depicted her as a pampered wife distraught because her husband's computer business wasn't making enough money to pay the bills.
They also seized upon a journal entry Darlie had made while suffering from postpartum depression after the birth of her third son, Drake. It was written just one month before the killings and addressed to her three boys.
"She said, 'Forgive me for what I'm about to do,'" says Shook. "She was contemplating suicide."
To the prosecution, the motive was clear: A depressed, self-involved Darlie had killed her boys in an attempt to maintain an extravagant lifestyle. Darlie's family pooled their resources and hired two high-powered defense attorneys, Doug Mulder and Richard Mosty.
On Jan. 6, 1997, the jury heard opening arguments. Although cameras were banned, both sides played to the media outside. Author Barbara Davis also watched every minute of testimony in the standing-room-only chambers.
The state began building its case by recounting its long list of circumstantial evidence, including testimony from a forensics expert who told the jury that fragments from that garage window screen which had been cut were found on a second knife in the Routier kitchen.
Prosecutors believe that, at some point, Darlie cut the garage window screen with that second knife. Then, after stabbing her sons with the other knife, they say she ran down the alley to plant the bloody sock, raced back home, slit her own throat, finished staging the crime scene, and called 911.
But perhaps the most devastating evidence against Darlie was the infamous Silly String video - the local news crew video of Darlie and her family at the boys' grave, singing Happy Birthday to son Devon and spraying Silly String at the site.
"I could see a lot of people in that jury box having the same kind of reaction that I had had when I first saw it," says Davis. "They couldn't believe their eyes. They were disturbed by what they saw."
The defense, however, countered by attempting to discredit the DA’s circumstantial case. They also argued that Darlie could not have had the presence of mind to stage the crime scene. Plus, Darlie’s attorneys claimed there were no witnesses, no confession, and no motive.
"There is absolutely no reason for her to kill those children," says Mosty. But against the advice of her lawyers, Darlie took the stand, and withered under cross-examination by prosecutor Toby Shook.
“She claims to have amnesia, yet the amnesia was very convenient," recalls Shook. "If she needed to explain a piece of damning circumstantial evidence, she'd come up with a new story. She'd have a memory of it.”
The trial lasted nearly five weeks, and the case went to the jury on Jan. 31, 1997. The following day, the jury reached a verdict. Darlie Routier was sentenced to death for the capital murder of her son Damon.
In her account of the crime and trial, "Precious Angels" author Barbara Davis left no doubt that she also believed Darlie Routier was guilty as charged.
But just weeks after the book was published, Davis met with a source who showed her photos that were not presented to the jury.
"I saw a woman who fought for her life," says Davis, who claims that Darlie was covered in bruises that she couldn't have put on herself - places, in fact, where she couldn't have reached.
However, prosecutors and even Darlie's defense attorneys disagree with Davis, saying that every picture of Darlie's wounds was admitted into evidence.
"They were shown," says Davis. "They were considered. And they were argued at the trial."
But, there's something else: A police surveillance tape secretly recorded views of the boy's gravesite and revealed that, on the day of the infamous silly string celebration, the Routiers' first held a solemn memorial service for their boys.
Because of legal concerns about the hidden camera, the tape was never shown to jurors.
Convinced Darlie was wrongly convicted, her family enlisted the help of Texas millionaire Brian Pardo, who had spent his own money before to defend another Death Row inmate.
Pardo hired attorney Stephen Losch who developed two theories - including one which fingered Darlie's husband, Darin Routier, as a suspect. The motive: a $300,000 insurance policy on Darlie.
In the wake of these allegations, Darin Routier severed all ties with Pardo.
Dallas attorney Stephen Cooper also represented Darlie and filed an appeal in July 2001, claiming that Darlie deserved a new trial because her original defense attorney, Doug Mulder, had previously represented Darin Routier - which constitutes a conflict of interest.
"There is no question that she got a raw deal, that she got an unfair trial," says Cooper. "There's no question in my mind that she's innocent."
Just this past May, however, the Texas Court of Criminal Appeals rejected that appeal. And earlier that same month, Darlie's other attorney, Losch, passed away.
But the legal efforts continue to get Darlie another trial. Another appeal has been filed by another new attorney, claiming there is evidence important to the case that was not addressed in her 1997 trial - including a mysterious bloody fingerprint found at the crime scene.
The Routiers had Devon and Damon's bodies exhumed in May 2000 to take their fingerprints. Cooper claims that forensic testing indicates the partial print is from an adult and not one of Darlie's children - supporting his defense that an intruder was in the home.
But perhaps an affidavit signed last summer by Darin Routier is the most surprising in this case. In this document, Darin admitted that three months before the murders, he was looking for someone to burglarize his home for an insurance scam.
"Darin was confronted, denied the burglary," says Cooper. "The circle kind of got narrower and narrower and he ultimately admitted it."
In the same affidavit, however, Darin also says that Darlie had asked for a separation the night of the murders.
In addition, Cooper says there's something more that he'd like a new jury to hear: "We do have a new witness that was unknown at the time of the original trial." A witness, he says, who fears for her life and has declined 48 Hours' request for an interview.
This new witness claims that on the night of the murders, she saw two men walking by the side of the road around the time the boys were killed - one man who loosely matched the description of the intruder Darlie had just given police 10 blocks away. Less than an hour later, she saw a small black sedan leaving the area.
But whether any of these new leads eventually reveals a new suspect, one thing remains constant: Darlie Routier insists she is not the killer.
Now, more than seven years after the murders, Darlie's family and supporters carry on a public crusade to clear her name.
"I'm going to do everything in my power, for the rest of my life if that's what it takes to prove my daughter is innocent," says Darlie Kee, Darlie's mother.
"They've never come up here with anything new for us," says Davis. "They'll take the evidence that was presented, they'll tell the public that it was never presented. They'll reinvent the case."
Darlie Routier says the only thing she did that terrible night was try and save her sons.
"I have been robbed of so much. Not just with Drake, with Devon and Damon. I have been robbed," says Darlie.
"For the rest of my life, I have to wonder what they would have looked like, how big they would have been, how their voices would have been changing. I didn't do anything and this has been taken from me and it's wrong."
The fate of Darlie Routier's latest appeal now rests with the state of Texas. Her attorneys believe that their new evidence - the fingerprint on the coffee table, the new witness who saw the two men and the black sedan that night - will be strong enough to persuade a jury to free Darlie.
The prosecution stands ready to re-try the case.
Meanwhile, Darlie and Darin's youngest son, Drake, 8, visits his mother once a month - but they remain separated by bulletproof glass. He hasn't touched his mother in more than six years.