Attorneys prosecuting the man ultimately convicted of murdering Chandra Levy didn't have much to work with.

No eyewitnesses. No confession to police. The only DNA evidence of any consequence belonged to an unknown mystery man. And, oh yeah, for the first year she was missing, the whole world — including police — assumed that a congressman who had been having an affair with Levy was the culprit.

Even so, Salvadoran immigrant Ingmar Guandique was convicted Monday of murdering the Washington intern, nearly a decade after Levy went missing.

The guilty verdict officially resolves one of the nation's most sensational mysteries. Levy's disappearance in May 2001 made headlines around the world after her relationship with then Rep. Gary Condit, D-Calif., was revealed.

Condit was initially a prime suspect of police, but when Levy's remains were found a year later in the city's Rock Creek Park, attention began to shift toward Guandique. He had been serving a 10-year sentence for assaulting two women in the park around the time Levy went missing.

Still, prosecutors did not bring formal murder charges against Guandique until 2009, and many courtroom observers speculated a guilty verdict would be difficult to obtain.

Assistant U.S. Attorneys Amanda Haines and Fernando Campoamor-Sanchez built their case on two pillars. One was compelling testimony from the two women Guandique attacked, which established a pattern that fit the Levy case. The other was testimony from a prison inmate who said Guandique confided to him that he killed Levy.

Prosecutors successfully downplayed the fact that no DNA evidence implicated Guandique, and that unknown male DNA was found on Levy's running tights. They argued that it likely resulted from contamination during the testing process, though they apparently never tried to match the DNA to technicians who handled the clothing.

And they overcame testimony from Condit himself, who took the stand and continued to evade questions about whether he had a sexual relationship with Levy, even as defense attorneys suggested he was acting "like a guilty man."

Bernie Grimm, a lawyer with the Cozen O'Connor firm who has represented high-profile defendants in D.C. Superior Court, said that while there was plenty of reasonable doubt that could have led a jury to an acquittal, he was still not surprised by the conviction.

"The government had an overwhelmingly strong emotional case," said Grimm, who witnessed parts of the trial. The emotion came from the two women, Halle Shilling and Christy Wiegand, who recounted their attacks, and from Levy's mother, Susan Levy, who attended the entire monthlong trial and was a visible reminder to jurors of her loss.

Mark Schamel, a former prosecutor now with the Womble Carlyle law firm who is familiar with D.C. Superior Court, agreed that emotional evidence can help overcome other deficiencies. He noted that prosecutors presented testimony from Shilling on the first day of trial.

"Emotional testimony can change the tenor of a trial, and it can be impossible to sway it back," Schamel said.

And while juries often have reason to doubt jailhouse snitches, the testimony of Armando "Mouse" Morales, a cellmate of Guandique in 2006, may have proved an exception. Prosecutors had planned to present testimony from other jailhouse informants, but they changed strategy after Morales' testimony.

"Morales was the hook that got the jury," Grimm said. His testimony "had a lack of exaggeration to it that made it convincing."

Morales, for instance, said that Guandique denied raping Levy and said the death was an accident. Guandique, according to Morales, was worried that other inmates would label him a rapist if they found out he was linked to the Levy case.

Guandique, had he been acquitted, would have been scheduled for release and deportation to El Salvador within a matter of months. He now faces a maximum sentence of life in prison. His attorneys have not said whether they will appeal. But on Tuesday, defense lawyers asked for and received a extension of time to file a motion requesting a new trial.