Young Christopher Singleton needed a ride to speech therapy class. His mother had the flu, so she asked her estranged husband for a favor.

Singleton’s father, Lawrence Davis, drove to the house, sat his 6-year-old son in the blue Oldsmobile and dashed back inside. Christopher heard screams: “Somebody help me!” Then Davis came downstairs and drove his son to class.

Elizabeth Patrice Singleton was found dead that day, March 1, 1999, curled up on the floor of her apartment. She was stabbed 11 times in her chest and torso, an autopsy found.

Christopher told authorities what he remembered, but the investigation stalled. Police were reluctant to accuse Davis based on a child’s testimony, family members and authorities say. The lead detective and prosecutor left their jobs, DNA test results gathered dust and the search for witnesses languished.

Nobody was charged for years. Authorities now admit mistakes with the investigation they call an unusual and extreme breakdown.

Sometimes justice is delayed. In this case, it took more than a decade. In November, a jury found Davis, 47, guilty of first-degree murder in his wife’s death. He is scheduled to be sentenced Friday and could spend the rest of his life in prison.

Christopher, meanwhile, is forging ahead. “I couldn’t let this stop me from living my life,” he says. Physically unharmed during his mother’s killing, he was nevertheless indelibly shaped by it.

He is now a tall, thin man of 19. He rarely thinks about his father, whom he saw for the first time since he was 6 during the murder trial.

He is reserved and wary. The letters “F.O.E.” — for “Family Over Everything” — are tattooed on his biceps. And he is a father himself: 3-year-old Crystal Elizabeth has her grandmother’s brown doe eyes. They laugh at children’s television together; they walk together to and from her day care.

While she is away, he fills out job applications and cleans the Columbia Heights apartment they share with her mother, his former girlfriend.

And he wrestles with his recollections. In the murder’s aftermath, prosecutors urged family members not to discuss the case with Christopher, worried about weakening the boy’s testimony. In the years that followed, the family rarely spoke of the killing and Christopher kept to himself.

He is still learning details of his parents’ relationship and wishes things were otherwise. “Nobody wants to think their father killed their mother,” he said.

There were warnings. In September 1998, Singleton told police that Davis punched her in her face and body, threatening to kill her if she reported his actions, according to court records. A day later, she obtained a court order that required him to stay at least 100 feet away for a year.

Singleton and her sons — Christopher has two brothers, Calvin, 21, and Kevin, 25 — moved from the family’s Edgewood home to Southeast Washington. But Davis petitioned to see his children during their separation, allowing him to remain close, said Ivy Moorefield, Elizabeth Singleton’s youngest sister.

In mid-December, a thinly dressed Singleton turned up at Eastern Senior High School, blocks from her home, on a wintry afternoon, according to court records and trial testimony. She told school officials that Davis had held her hostage with a gun for a week, raping her repeatedly.

He was soon arrested. But authorities dismissed a sexual assault charge against Davis the day after his arrest, according to court records, because Singleton “waited a week to report the rape and allowed [Davis] to stay in the house.” Bill Miller, a spokesman for the U.S. Attorney’s office, declined to elaborate on that decision.

As he left the courtroom after the charge was dropped, according to court documents, Davis whispered to his wife: “You broke your promise. Now it’s time to die.” He was charged with threatening Singleton, and a trial was set for March 24, 1999.

Singleton alleged that Davis came to her home twice more, violating the restraining order. But she didn’t let him in, according to court documents, and he was not arrested in either incident.

On March 1 — with Singleton weakened by the flu, their older sons off to school and her youngest waiting in a car — Davis got inside.

Singleton may have sensed danger. Weeks before she was killed, she told family members she did not want Davis raising her sons if something happened to her, Moorefield said.

“She was scared,” Moorefield said recently. “She told us he was going to kill her and get away with it because the system failed her.”

It is not known whether Singleton intended to let Davis into her home that morning. There was no sign of forced entry. But “why would she fear for her life knowing her young son was only feet away sitting in the front seat of the car?” Assistant U.S. Attorney Amanda Haines said in the November trial.

Singleton, 32, was found dead in the fetal position near a living room sofa, cold medicine and orange juice, according to court documents.

The investigation crumbled, according to Singleton’s family members and individuals in law enforcement, as the file passed through three sets of detectives and prosecutors.

It “dropped through the cracks,” a law enforcement official said recently. Singleton did everything she could within the law, Haines said during the trial, but “had not received justice in her lifetime.”

Police and prosecutors took the case up again only after a chance conversation between Moorefield and former homicide detective Ben Collins in 2007. Moorefield was working in technical support for the city government when Collins called for assistance, and she brought up her sister’s case.

Collins told cold case detective Jeffrey Williams about the conversation. Williams took the case to Haines and her colleague Sharon Donovan, who found a DNA report linking Davis to Singleton’s dead body. The report sat in files for nearly a decade after Singleton’s autopsy. The trio also unearthed a witness who said he saw Davis at Singleton’s house on the morning of the murder. The witness, a neighbor, had never been questioned by police.

Davis was arrested in June 2009.

George Kucik, commander of the D.C. police’s criminal investigation unit, said there were “issues that need to be checked” regarding the case. “If mistakes were made, we will make every effort to improve,” Kucik said in a recent e-mail.

The wait left Christopher Singleton and his family frustrated and angry. “I don’t believe in this justice system,” he said recently. “They don’t do what they’re supposed to do. They do what they want to do.”

Singleton took the stand in November in D.C. Superior Court, recalling the March morning he waited for Davis in the Oldsmobile. He avoided his father’s eyes.

Haines presented the DNA evidence and the neighbor testified. Davis’s attorneys argued that prosecutors charged the wrong man, and he did not testify. After three days of deliberations, the jury convicted him.

Christopher and his brothers were sent to live with an aunt in Charleston, S.C., after their mother’s death. Christopher recently graduated from high school there and moved back to the District, where he is preparing to take the SAT — he plans to study business in college — and helping to raise his daughter.

“I want to make myself better for her so she can have a better life,” he said.

Christopher says his mother “sent” Crystal to him, and he brightens when he talks about his daughter.

But he often remains guarded. His head is frequently bowed over a cellphone, which he uses to tweet and send text messages. Crystal’s mother, 19-year-old Howard University student India Stevens, says he can be distant, isolating himself when angry and refusing to discuss his feelings. Sometimes, she says, he feels as though “the world is against him.”

Singleton has changed his middle name. Once Lawrence, after his father, he now uses the name Travis, for an uncle who was shot dead in the District a decade ago. The last contact between father and son was seven years ago, when Davis wrote Christopher a letter. Christopher did not respond.

“I really don’t have anything to say to him,” he said.

Christopher, Calvin and Kevin all live on the same block. They are best friends, and they record rap songs together at a local studio. Each has the words “My Brother’s Keeper” inked across his chest.

Christopher has two other tattoos he got when he was 15. The words “Life” and “Death” mark his wrists.