Ingmar Guandique was charged with the 2001 killing of 24-year-old Washington intern Chandra Levy, but all charges were dropped on July 28 when new information came to light. (Video: WUSA9 / Photo: AP)

Babs Proller met the man when she was living in a Maryland hotel. He had helped the local actress carry her dog, Buddy, to her fourth-floor room, and over the course of several days in early July, the two neighbors became friendly.

She soon learned that her new acquaintance, Armando Morales, was a convicted felon and former gang member, recently released after decades in prison. He was also the star witness in one of the Washington area’s most sensational murder trials.

Proller eventually became suspicious of Morales and began recording hours of their conversations. Eventually, she contends, Morales revealed a secret that she caught on tape, telling her that he had lied when he testified in 2010 that a onetime cellmate had confessed to killing Chandra Levy.

Those clandestine recordings led to a stunning announcement by District prosecutors on Thursday that they would drop all charges against Ingmar Guandique, who was facing a retrial in the 2001 slaying of the federal intern, according to Proller and individuals familiar with the investigation.

The Washington Post could not independently verify the content of the recordings or the accuracy of Proller’s description. The U.S. attorney’s office would not comment on Proller’s account and said only that “new information” uncovered this week had led prosecutors to conclude that they could not prove their case beyond a reasonable doubt.

In this May 28, 2002, photo, photographs of Chandra Levy are diplayed at her memorial service in Modesto Centre Plaza in Modesto, Calif. (Debbie Noda/AP)

Two officials with knowledge of the investigation declined to discuss details of the recordings but said that the audio led prosecutors to question Morales’s credibility.

The dropped charges — coming just three months before the retrial was set to begin in the 15-year-old case — bolsters arguments made by Guandique and his attorneys, who have steadfastly said he was being wrongly held. They had insisted that Morales was making up his account to gain favor with authorities. It also leaves one of the nation’s most infamous murder mysteries unresolved.

In a statement, the D.C. Public Defender Service noted that Guandique “has maintained since the beginning, when he passed an FBI administered lie detector test, that he did not kill Ms. Levy.”

“It is now clear that the jailhouse informant, who was central to the government’s case, was a perjurer who too easily manipulated the prosecutors,” the attorneys said in the statement.

Levy was a 24-year-old intern with the Federal Bureau of Prisons when she disappeared on May 1, 2001. Her remains were found in 2002 in Rock Creek Park.

The intern’s disappearance and killing captured national attention when it was revealed that she had an affair with then-Rep. Gary A. Condit (D-Calif.), who was married and 30 years her senior. Police initially focused on Condit as a suspect but later cleared him.

Years later, authorities charged Guandique in the case, alleging that he had killed Levy while she was jogging in Rock Creek Park. He had pleaded guilty to attacking two other women in the park about the same time Levy was killed, and prosecutors argued that he was a predator who also attacked Levy.

Proving their theory was difficult from the start. There was no forensic evidence and no eyewitness. The heart of the prosecution’s case rested with Morales, who said he shared a cell at a Kentucky prison with Guandique in 2006.

Morales, a five-time convicted felon, captivated D.C. Superior Court with his testimony. He took the stand on the eighth day of the 2010 trial and was the first to directly link Guandique to Levy’s death.

According to Morales, Guandique had said: “You don’t understand. . . . Homeboy, I killed the [expletive], but I didn’t rape her.”

Morales told the jury that Guandique had said he saw Levy carrying a waist pouch and thought there would be cash inside. He recounted how he grabbed her from behind, Morales said, and dragged her off the trail.

She tried to fight, according to Morales’s account of his cellmate’s purported confession, but by the time Guandique got her into the bushes, she had stopped struggling. Morales testified that Guandique told him that he thought Levy was unconscious, not dead.

Guandique claimed that he took Levy’s pouch and fled, Morales said.

“He said he never meant to kill her,” Morales testified.

Morales said in court that Guandique confided in him because he feared he was about to be transferred to a new prison where inmates might view him as a rapist for the attacks on the two other women and target him in a way that they wouldn’t target a killer.

Morales spoke slowly about the man he called “Chucky,” a reference to the murderous doll in the 1988 horror movie “Child’s Play.” He pointed to Guandique in the courtroom and said Guandique had the nickname tattooed across his back. A photo of the tattoo was shown to the jury of 12 women and four men. Morales said he remembered the tattoo in part because “Chucky” was misspelled: C-h-a-c-k-y.

The men bonded over their gang affiliations. Morales, who pleaded guilty in 1997 to dealing cocaine and methamphetamine while armed, was serving a 21-year sentence. He was a founding member of the Fresno Bulldogs, a gang based in California and aligned with Guandique’s gang, Mara Salvatrucha, or MS-13, prosecutors said at the time of trial.

At the close of the trial, Guandique was convicted and sentenced to 60 years in prison.

Over the following years, Guandique’s attorneys challenged the conviction. They argued that it “was based on a lie” spun by Morales and said the government had failed to reveal that their witness had previously cooperated with law enforcement as a prison informant.

Last year, the conviction was overturned after prosecutors dropped their opposition to defense requests to have a new jury hear the case. The trial was set to begin in the fall.

In documents filed with the court, Guandique’s defense attorneys said they were considering a strategy for trial in which they would argue that Condit or someone else had a motive to kill Levy.

In a statement released Thursday, Condit’s attorney said the former congressman was “extremely disappointed” that the case had been dropped.

“The failure of authorities to bring formal closure to this tragedy after 15 years is very disappointing but in no way alters the fact that Mr. Condit was long ago completely exonerated by authorities in connection with Ms. Levy’s death,” the statement read.

Guandique, an illegal immigrant from El Salvador, has been jailed awaiting retrial. After his release, he will be placed in the custody of U.S. Immigration and Customs Enforcement, where he faces removal proceedings, officials said.

Proller said that she and Morales met July 6.

During their conversations, Proller said, Morales had threatened to hurt her ex-husband, which prompted her to begin recording their discussions. Proller said she thought the recordings could protect her and she didn’t want to be implicated in any crimes against her ex-husband.

Proller sent The Post cellphone images of Morales’s prison identification and photos of Morales.

Over the course of three days, “he told me his life story,” Proller said. “He said he is a key witness in a major murder case.”

According to Proller, he lied about Guandique’s confession to improve his prison conditions and eventually struck a deal with prosecutors in exchange for his testimony.

Proller said she told Levy’s mother, Susan Levy, about the recorded conversations with Morales. Susan Levy then contacted the authorities, Proller said. Proller said she turned over the recordings to prosecutors, with whom she has been in contact since Friday.

Calls to Susan Levy were not immediately returned.

Although recording another person without their consent is illegal in Maryland, Proller said prosecutors told her that they were not going to pursue charges against her.

Proller, who according to an IMDB page has appeared on the Netflix TV series “House of Cards,” said some of the details of her involvement in the Levy case sound like an episode of the show.

But she said she wanted to come forward to help Susan Levy, a grieving mother.

“I want the true person who did this to be found,” Proller said. “The system failed and took attention away from somebody who really did it. It’s a never-ending nightmare for this poor family, and they need closure.”