A jogger found her body on a cold afternoon in November, along a bicycle trail that runs through the woods near Suitland Parkway and Barry Farm in Southeast Washington.

Antina Cindette Pratt, 40, had been stabbed 29 times, her family said. Her cellphone was missing, but her ID, backpack and purse were all there.

D.C. police identified a suspect in January — Elliott Avery Starks, 34 — who lived in the same apartment complex as Pratt on Pomeroy Road, a short walk from the bike trail. Starks has not yet been arrested, but authorities recently added new urgency to their search for him, announcing that the FBI has joined the manhunt.

The Safe Streets Task Force, a group of FBI agents and D.C. police officers, is now helping in the case. While the task force typically focuses on violent drug trafficking and gangs, in this case it is working to find the suspect, who Pratt’s family believes has fled south.

Along with the statement from the FBI came a new revelation.

Antina Cindette Pratt, 40, is shown in this undated family photo. She was found fatally stabbed Nov. 8, 2016, in the District’s Barry Farm neighborhood. (Family photo)

Starks, charged in a warrant with first-degree murder in Pratt’s death, had been convicted of murder.

Five months before Pratt was stabbed, Starks had been released from prison after serving 16 years for killing a man at the same apartment complex on Pomeroy Road. He was 16 when, in 1999, he shot the unarmed victim in the head during a dispute between two families in a crowded hallway, according to court documents. He was charged as an adult, pleaded guilty to second-degree murder and was sentenced to 14 to 42 years in prison.

Pratt’s oldest sister, Alecia McDonald, has waged a relentless campaign with police to not give up on the case.

“We’ve been searching for clues since the day it happened,” said McDonald, who lives in Greenbelt, Md. “It doesn’t get any easier. We understand how it feels to not have the guy who did this, and not be able to look him in the eye and ask him, ‘Why? Why 29 times?’ It is clear to us that whoever did this did not want her to survive. The reason? We don’t know. We need him to stand trial. We need to face him so he understands he has broken our family.”

McDonald said it is not clear whether her sister knew Starks. Police have released surveillance video taken Nov. 8, the night before Pratt’s body was found. It shows a person who appears to be Pratt, wearing a backpack, meeting up with a man police say is Starks in the apartment parking lot before they disappear into the woods. The sister said police have shown her, but not released publicly, a second video showing the man emerging from the woods 30 minutes later. McDonald said he was alone.

“Antina was so generous, so willing to sometimes trust people too quickly,” said McDonald, noting that it appears from the video that her sister and the man walked together as if they knew each other. Pratt had just come from a bus stop on her way home from a job as a waitress. “We have looked at this video over and over,” McDonald said. “What is the connection? Why wasn’t her boyfriend there that night? . . . She didn’t appear to be nervous or scared. We made the conclusion she felt comfortable enough to talk to this person.”

Photographs of Elliott Avery Starks, 34, who is charged in a warrant with first-degree murder in the stabbing death of Antina Cindette Pratt. The photo on the left is from 1999 and the one on the right is from June 2016. (D.C. police )

Pratt’s family spoke first to WTTG’s Fox-5 TV station.

Pratt was one of four daughters born into a family that lived in Northeast Washington. Her mother died when she was a week old, and she and others were raised by their grandmother. For a time, Pratt lived a normal, although difficult life. A single mother of three sons, she worked with developmentally challenged children in D.C. charter schools and owned a house in Northeast.

But McDonald said financial troubles overwhelmed Pratt. She said her sister lost her home and then her job, and for years she and her sons lived out of a small car, too proud to ask relatives for help.

“She had a generous heart and the most bubbly of smiles,” McDonald said. “She loved people, and people truly loved her. She was trying to [be] the best mom.” Her sons are now 17, 19 and 22. McDonald said Pratt took particular joy in her job. “She loved that the children would smile at her when she came into the classroom.”

Shortly before she was killed, Pratt got a job as a waitress at a Denny’s restaurant in the District, and moved in to the Pomeroy Road apartments with her boyfriend and his family. Her youngest son was with them. Starks and his family lived one building away. McDonald said she is not in contact with the boyfriend.

Pratt’s family does not believe her killing is related to the fatal shooting in 1999. Starks’s attorney in the murder trial did not respond to interview requests. Starks’s relatives could not be reached.

Court documents filed in connection with the fatal shooting in 1999 show that Starks had an extensive juvenile record before the killing, including gun offenses. At the time of the shooting, he was on juvenile probation for carrying a firearm. He argued self-defense.

Judge Ann O’Regan Keary, who sentenced Starks, urged the D.C. jail to ensure that he receive counseling while in prison, noting his “youth and immaturity, and his tendency to act on emotion rather than reason.” The judge said significant monitoring would be needed to further Starks’s “development from boyhood through adolescence into manhood.”

Keary warned that even if Starks served the full 42 years, he will still “have a substantial portion of his life to live upon release. Given the poor history Mr. Starks already has handling difficult situations, it is clear that if he is left untreated, he will remain a severe danger to the community.”

It could not be learned what programs, if any, Starks received in prison, and now authorities are hunting him again. “It’s been eight months but it’s as if we’re still in November 8 and this just happened,” McDonald said.

Of Starks, she said, “How far can you run?”