In Spring 2001, the mysterious disappearance of Chandra Levy rocked the nation.
In a case that could have been likened to a plot of a thriller, the 24-year-old master's student vanished without a trace on May 1, raising a mixture of publicity and fear throughout the country.
A year before her disappearance, Chandra had moved to Washington D.C. to intern with the Bureau of Prisons for her master's program at the University of Southern California. She was studying public administration in hopes of one day working for the FBI.
"She managed to be working for the state here [in California] at the governor's office, and also the mayor of Los Angeles," Chandra's mother, Susan Levy told 20/20's Deborah Roberts. "She had these high political internships. ... She was an honor student, had good grades ... maybe a student aggressive enough to go after these really good positions."
On May 6, Levy's parents alerted authorities they had not heard from their daughter in the past five days. With no initial indication of foul play, it came as a shock when Chandra's father, Robert Levy, revealed she was having an affair with an older, married U.S. congressman, who he believed to be U.S. Representative Gary Condit.
Brad Garrett, a former FBI agent who was the lead investigator in the case, said the couple became involved after Chandra and a friend visited his office and he gave them a tour of the Capitol.
After the pair began their affair, Garrett said Chandra "led a very insulated life once she started this relationship with Gary, because the only time[s] she'd really see him were after hours. Her life basically going to [work], back home and then to Gary's house."
One year after the extensive search, Chandra's body was inadvertently found at Rock Creek Park by a man on a walk with his dog. But when Condit was cleared of the crime, the crime became a cold case, as there were no other potential suspects.
It would take eight years before the police found a lead. They arrested a man named Ingmar Guandique, an undocumented immigrant from El Salvador. He had recently been convicted of attacking two other women at the same park, around the same time of Levy's disappearance. In 2010, Guandique was convicted of Chandra's murder and sentenced to 60 years in prison. It appeared the nightmare was finally over.
But six years later, Chandra's murder case was reopened when it was discovered the jailhouse informant - who helped seal a conviction - had lied when he testified on Guandique's guilt.
Guandique's conviction was overturned, and a retrial was set for October 2016. But prosecutors admitted they didn't have enough evidence to prove he was guilty beyond a reasonable doubt, and the case was ultimately dismissed.
A statement from the U.S. Attorney's Office for the District of Columbia said the charges against Guandique were dropped due to "recent unforeseen developments that were investigated over the past week."
Chandra's mother said when investigators had informed her family about the informant's incriminating audio recordings, they were left devastated once again, losing the solace they believed they finally had.
"It's been very hard. I feel shattered ... it's hard to accept that my daughter's death is a cold case again. Many cold cases don't always get solved," Susan told PEOPLE. "You know you won't ever get your child back, but you want to know what really did happen."
"There's never closure, and these wounds, they don't heal," Susan added. "They scab over and then they get picked at. It is hard for us, and it has affected our whole family. But it is what it is. I think my daughter would have contributed a lot to the world."
Chandra's brother, Adam Levy, said when he heard that Guandique's conviction had been overturned, he felt a mixture of anger and disappointment.
"My faith in the system has been changed," Adam told 20/20. "I had innocence before everything happened. ... It stole my innocence. It's hard to see things as bright."
But just because Guandique's conviction had been overturned, it didn't mean he escaped without consequence.
According to TODAY, Guandique illegally entered the United States and was a documented member of the internationally known MS-13 gang, with whom he had committed violent crimes.
"Mr. Guandique unlawfully entered the United States, and once here, continued to violate U.S. laws by assaulting innocent victims," Matthew Munroe, the acting head of the ICE Enforcement and Removal Operations field office in Washington, said. "As a result of his actions, he has been removed to his home country of El Salvador."
In October 2016, Condit went on The Dr. Phil Show, to break his silence on the tragic cold case.
He told host Phil McGraw that while he originally planned on staying out of the limelight, his children convinced him to "set the record straight" and tell the world his version of events.
While he wrote the book, Actual Malice: A True Crime Political Thriller, the former congressman declined to discuss his relationship with Chandra in detail.
Despite admitting to authorities that he did in fact have an affair with the young intern in 2001, Condit now denies the pair ever being romantically involved.
"Dr. Phil, I haven't answered that question [about possible romantic involvement] publicly for 15 years and I'm not going to change my position or my view on that today, or probably any time in the future," Condit said.
"Not only is it not relevant," Condit explained, "I think people are entitled to some level of privacy. We have lost our common decency in this country, and I have decided to draw the line there."
"I did not have a romantic involvement with her," he concluded. "I was not involved in her disappearance ... in any way."
However, when Chandra's mother saw the interview, she told PEOPLE she didn't believe a single word from Condit's mouth.
"That's not true," Susan said. "I think he's running scared. I think he's trying to clear his name. There was definitely something going on between my daughter and him, unfortunately."
"Chandra was secretive about her relationship with Condit. Chandra shared that her 'Man,' as she called him, was high-profile and it was best to not be seen together," she later told ABC News.
With Guandique being exonerated of the crime, and Condit denying any culpability, Susan said she thinks about Chandra every day, and hopes to one day find out who murdered her daughter.
"I want someone to come forward and tell the truth," Susan told 20/20. "Someone knows something that I don't know. ... I don't think my daughter would run in the park by herself."
"I guess I'll always have unanswered questions, but it's just sad," she said. "And the story is, to me is, for women who are interns, to be very careful who they meet."
"There's never a day that I don't think about her. ... Our future, grandkids and time that we would have spent together."
We can only hope Chandra's murderer will one day be found.