Darlie Routier was convicted and sentenced to die for fatally stabbing her 5-year-old son, Damon, in June 1996. More than two decades later, the Rowlett woman remains in prison — one of only six women on Texas' death row.

Darlie Routier, 1996 (Judy Walgren / 92301)

Devon, 6, was also slain, but Routier was convicted of only one murder because prosecutors decided to ensure the option to pursue a second indictment if the first trial didn't net a lasting conviction.

Routier has maintained an intruder broke in while she slept and killed her sons before she chased him away. She said she could not remember much of what happened that night, and a psychiatrist for the defense said she was a victim of "traumatic amnesia."

But prosecutors called that a convenient excuse and argued Routier killed her children because they interfered with the life she wanted to live.

The Last Defense, a seven-part documentary series that focuses on the death row cases of Routier and Oklahoma man Julius Jones, airs Tuesdays at 9 p.m. on ABC.

Viola Davis and Julius Tennon are the executive producers of the series, which the network says "explores and exposes flaws in the American justice system."

These court cases deserve a 2nd look. I’m proud to say I’m executive producing a gripping docuseries on ABC called #TheLastDefense, premiering tomorrow at 10|9c. pic.twitter.com/UyzoQBcynR — Viola Davis (@violadavis) June 11, 2018

Following is a look at five moments that helped define the Routier investigation, trial and the aftermath of her conviction:

The 911 call

During Routier's death-penalty trial, jurors heard a 6-minute 911 call from the night of the attack. Prosecutors said the call supported what officers said about Routier's behavior, but the defense said the recording showed she was traumatized and distracted by the chaos in her home. They argued Routier should not be held accountable for what she said or did during that time.

Devon Routier (left) and his brother Damon pose in a 1995 Easter photo in Rowlett. Their mother, Darlie Routier, was sentenced to death for the murder of Damon Routier. (The Associated Press)

In the recording, Routier tells the dispatcher that she touched the knife, the suspected murder weapon, and added, "I wonder if we could have gotten the prints maybe."

She mentions her husband ran downstairs but doesn't ask about their infant son, Drake.

Officers testified that Routier was upset and screaming, but didn't appear to be in shock and seemed very alert. One officer said he told Routier to apply pressure to the stab wounds on Damon's back as he gasped for breath, but instead, she did nothing.

"I thought if she was worried about fingerprints on a knife, she could certainly take care of her kids," Officer David Waddell said during the trial.

He added that she did not follow paramedics when they carried Damon to an ambulance and did not ask where they were taking him.

Bloody evidence and the garage escape

Over and over, Routier, who was 26 at the time of her sons' murders, said a man wearing dark clothes and a baseball cap attacked the boys, then her, before escaping through the garage.

But investigators said evidence at the scene was inconsistent with Routier's account.

Investigators found no blood in the garage or on the garage window or wooden fence surrounding the backyard. The window sills in the garage had layers of dust, and the mulch in the flower beds between the garage and the backyard gate was undisturbed, an arrest warrant stated.

Lab tests did find fingerprints on the garage window that did not belong to Routier, her husband or law enforcement, but it's unclear who left them.

1 / 3The stab wound on Darlie Routier's neck.(Dallas Morning News File Photo) 2 / 3This fingerprint document, reportedly to show the fingerprints of Devon Routier, was copied in the law office of Stephen Cooper. (Jim Mahoney / File ) 3 / 3Richard Burr, one of the lawyers for Darlie Routier, shows the position of an unidentified finger print on a map of the Routier home as they talked about the latest developments in her case in 2004. A state district court refused to to examine evidence that they believe points to her innocence. The news conference was held in front of the Frank Crowley Courts Building in Dallas.(Michael Ainsworth / File Photo)

Routier said she found the knife on the floor in the utility room, but investigators didn't find any blood splatter or other marks that would have indicated the knife was dropped there.

Blood was found near the kitchen sink, but no appreciable amount on the couch where Routier said she had been stabbed. There had been attempts to clean the countertop and sink before police arrived, and police suggested that she may have inflicted the wounds herself, the affidavit stated.

Police said a bloody sock was found on the grass several houses down. Routier's relatives cited it as evidence that someone else killed the boys, and the defense said there was no way Routier would have had time to stage the crime scene.

Much debate also centered around a bloody fingerprint on the coffee table near her son's body. Part of her appeal centered on the print belonging to an adult, not one of Routier's slain children.

The print was never compared to the children's fingers because morgue workers did not take the children's prints, which is usually standard procedure.

In 2008, a federal judge granted additional testing of the sock, a butcher knife, the fibers from another knife and gave permission to run four fingerprints through a national database. The DNA was submitted last year for testing, but there have been no other recent updates.

An image from a rebroadcast of the 1996 video NBC5 captured of Darlie Routier spraying Silly String on her sons' graves. (KXAS-TV (NBC5))

The Silly String video

Days after the boys' deaths, the Routiers held a graveside birthday party for Devon on what would have been his 7th birthday.

They sprayed Silly String on the grave and sang "Happy Birthday." KXAS-TV (NBC5) recorded the celebration and interviewed the couple, who said they had nothing to hide.

Routier was arrested four days later and charged with capital murder.

The NBC5 footage of the Silly String and a smiling Routier was shown during the trial. Prosecutors said her behavior at her children's graves showed a lack of grief and remorse.

Defense attorneys said the tape showed a family trying to cope with grief.

It was not the only time jurors heard statements about Routier's lack of remorse.

An emergency room doctor testified that the mother seemed emotionless when he tended to the knife wounds to her neck, shoulder and forearm. Dr. Alex Santos called the wounds "superficial," but agreed that they came millimeters from cutting her carotid artery.

A nurse's note, however, described Routier as "very emotional, crying, sobbing and talking about events in her family."

1 / 3Darin Routier cleans the gravestone of his two slain sons, Devon and Damon, at Rest Haven Cemetary in Rockwall in June 1997.(Joe Stefanchik / File) 2 / 3ORG XMIT: [NM_3RoutierCustody#1 ] Headline: Caption: 7-3-96 --- (MAGAZINES OUT) Darlie Routier of Rowlett, ctr, bites her fingers during testimony at a child custody hearing involving her surviving child, 8-month-old Drake Routier, at the Photographer: Title: Credit: City: State: Country: Date: ObjectName: NM_3RoutierCustody#1 CaptionWriter: Special: Category: SupCat1: SupCat2: SupCat3: Source: Keyword: 7-3-96 Keyword: Darin Routier Keyword: Darlie Routier Keyword: Rowlett Keyword: Henry Wade Juvenile Justice Cen Keyword: Sarilda Routier Keyword: Routier Keyword: Drake Routier Keyword: Metro Keyword: 92794 Keyword: Randy Eli Grothe Keyword: NM_3RoutierCustody#1 3 / 3ORG XMIT: DN104 ADVANCE FOR DEC. 15--FILE--Darlie Routier, standing, poses with her husband Darin and two sons Damon, left, and Devon in this 1993 family photo at their Rowlett, Texas, home. Darlie Routier is currently in the Dallas County jail awaiting trial for the murder of two of her three boys. (AP Photo/ho)(AP)

The gravesite recording

During Routier's trial, a detective testified that investigators hid microphones near the boys' graves in Rockwall before Devon's birthday in the hopes that someone might make a confession that would lead police to the killer.

In 1997, after an FBI investigation, U.S. Attorney Paul E. Coggins announced that the Rowlett Police Department would not face federal charges for planting the hidden microphones.

Attorneys and others questioned the legality of the move.

The investigation determined that the decision was based on legal advice indicating the technique was lawful.

In June 1998, Routier's mother and husband filed a lawsuit accusing the police detectives and a prosecutor of invading their privacy. The suit was later dismissed.

The trial transcript

Court transcript problems became central to Routier's appeal, which was delayed because of the issues.

Following the trial, one of Routier's attorneys found errors in the transcript, which was needed for an appeal. Court reporter Sandra Halsey refused to answer questions, and a state district judge ordered a review.

Darlie Routier, on death row for the murder of her 5-year-old son, turns at the close of her court hearing in Dallas on Oct. 30, 1998. Flanking Routier are her attorneys Stephen Cooper (left) and Steve Losch. At rear is Judge Robert Francis. (LM Otero / The Associated Press)

In 1999, a complaint filed with the state board alleged that Halsey's work was "incompetent, inaccurate, unprofessional and untimely" and that she lied to hide mistakes.

She was ordered to pay $32,265 for the cost of getting the transcript fixed and had her license revoked.

A second court reporter who was appointed to reconstruct portions of the transcript using Halsey's audio recordings, stenographer's notes and the original transcript said the first version contained 18,000 errors.

She also had to make a new version of 53 pages of the transcript detailing pretrial issues and preliminary jury selection using stenographic notes rather than audio recordings after Halsey reportedly could not find the tape.

Finally, in November 1999 a judge approved the revised transcript. Routier's team filed an appeal in 2001, but in 2003 the Court of Criminal Appeals rejected Routier's claims and upheld her conviction.