The man convicted of killing Washington intern Chandra Levy is expected to get a new trial after his attorneys argued a key witness in the 2010 trial lied. (Reuters)

The man convicted in the 2001 killing of federal intern Chandra Levy is likely to get a new trial after prosecutors on Friday dropped their long-standing opposition to defense efforts to have a new jury hear the case.

Since 2013, attorneys for Ingmar Guandique, 34, have argued that a key witness in the 2010 trial had lied when he testified that Guandique, his onetime cellmate, confessed to him that he killed Levy.

Guandique’s attorneys with the District’s Public Defender Service contend that the defense should have been told that the witness, a convicted drug dealer and gang member, had been cooperating with prosecutors in other cases. They said he made up the alleged confession from Guandique to gain favor with prosecutors.

Levy, 24, went missing May 1, 2001, and her remains were found a year later in Rock Creek Park, where she had gone jogging. The young woman’s disappearance and killing emerged as one of Washington’s most sensational murder cases when it was discovered that she had had an affair with Gary A. Condit, a married congressman who was 30 years her senior. Condit was the first suspect and later was cleared.

Chandra Levy (AP)

The prosecution’s decision sets up a redo of a case that was challenging for authorities from the start. There was no forensic evidence linking Guandique, a gang member, to the crime scene in Rock Creek Park, no murder weapon, no eyewitness and no definitive ruling from the medical examiner on what killed Levy. At Guandique’s 2011 sentencing, Judge Gerald I. Fisher imposed a 60-year prison term but noted that the government’s case “wasn’t a very strong” one.

In a filing late Friday afternoon, prosecutors wrote that the U.S. attorney’s office remains confident in Guandique’s guilt. Still, they wrote, the government would withdraw its opposition to the defense request for a new trial and asked for a status hearing in two weeks to begin to set a timeline for a retrial.

At the initial trial, prosecutors had presented a theory that convinced jurors that Guandique was the killer. Other women joggers had been assaulted by him in Rock Creek Park around the time of Levy’s disappearance, and they took the witness stand. In some of the most compelling testimony, the cellmate, Armando Morales, testified that Guandique had told him he was high on drugs, saw Levy walking alone with a waist pouch and attacked her for cash.

Susan Levy, Chandra’s mother, said in an interview Friday that another trial would be painful, but she wanted to be sure that “true justice” is done. She said a phone call from the U.S. attorney’s office alerting her to the development came nearly 12 years to the day after her daughter’s private burial on May 27, 2003, near the family’s home town of Modesto, Calif.

“I want to make sure the right person is caught and responsible for what happened. No matter what happens, it’s not going to bring my daughter back, but you want to know the truth of what happened to my daughter,” she said.

Unlike her husband, whom Levy said is “100 percent sure” that Guandique is their daughter’s killer, Levy said she has wavered.

Guandique and his attorneys have repeatedly said that he was not involved in Levy’s death.

“The government’s case against Ingmar Guandique was based on a lie,” Jon Anderson, one of Guandique’s public defenders, said Friday. “We are gratified that the government has now acknowledged that it cannot defend this conviction, and we look forward to justice being served in a new trial.”

The defense argument for a new trial, which had led to a series of hearings over two years, centered on Morales’s credibility. Those hearings were set to continue next week.

During Guandique’s trial, Morales testified that he had never cooperated with prosecutors in other cases in the hope of seeking favor from authorities. Defense attorneys said they found evidence that Morales was not truthful — and said prosecutors in the District either knew or should have known that.

In one hearing on the defense motion, a California prosecutor testified that Morales approached him in 1997 about cooperating in a different murder investigation. But the prosecutor declined the offer because he found the witness to be “treacherous” and not trustworthy.

Prosecutors have vigorously argued that neither they nor any officials in the U.S. attorney’s office or any homicide detectives had knowledge that Morales had offered to testify in other cases in exchange for favorable treatment.

The lead prosecutors in the case, Amanda Haines, Fernando Campoamor-Sanchez and Chris Kavanaugh, had been scheduled to testify next week about their handling of the case. In the motion, prosecutors said the “passage of time” had made it difficult to prepare for that hearing. They said they opted to stop fighting the defense request, although they did not concede any problems with their evidence.

“The government continues to believe that the jury’s verdict was correct,” prosecutors wrote. “The government also believes that nothing in the thousands of pages of information that have been produced about Mr. Morales . . . nor anything else revealed by the government’s comprehensive post-trial investigation, casts doubt on the defendant’s guilt of the murder of Chandra Levy.”

Prosecutors asked that Guandique remain in jail pending the outcome of the June 4 hearing. Fisher, who oversaw the first trial, will have to decide whether a new trial is warranted.

Former prosecutor Thomas G. Connolly said it was likely that prosecutors might not have been aware that Morales had cooperated with authorities on previous cases.

Still, Connolly who is now a defense attorney, said it’s “never good when there’s a conviction and a new trial is granted on major statements on behalf of a star witness. That’s not a good thing for any prosecutor.”

After Guandique’s conviction, one juror, Sharae Bacon, said Morales’s testimony convinced her that Guandique killed Levy. “There were no holes in his testimony,” she said.

The trial was the first high-profile case for then-U.S. attorney Ronald C. Machen Jr., who was named to the position in 2010. After the jury returned its verdict, Machen held a news conference applauding the prosecutors and detectives who worked on the case. Machen resigned from the office in March after five years in office and has since returned to private practice.

It remained unclear whether prosecutors will recall Morales to the stand to testify in a second trial.