(ARLINGTON, Va.) -- For nearly 25 years, Chris Johnson has been entangled in a deep mystery that he said has wrecked his family and his life.
It began in 1998, when Johnson found his fiancée Andrea Cincotta, 52, dead inside their Arlington, Virginia, apartment. She had been strangled and crudely stuffed inside a bedroom closet.
Although immediately under suspicion by the police, Johnson was never charged. Then things changed in 2018. Convicted rapist Bobby Joe Leonard alleged to investigators he was offered money by a man he believed to be Cincotta's boyfriend to kill her.
This led to Arlington prosecutors charging Johnson with murder-for-hire in November 2021.
Johnson, 61, pleaded not guilty to the charge. He has maintained his innocence, and still grieves for Cincotta.
"I'm sorry I wasn't there to protect her," he told ABC News' Ryan Smith in an exclusive interview with "20/20."
The "20/20" episode, which airs March 10 at 9 p.m. ET and streams on Hulu the next day, features more of the candid interview with Johnson, who was acquitted of his charge in October, footage from the police investigation and exclusive interviews with jurors.
Johnson returned home on Aug. 21, 1998, and said he couldn't find Cincotta, who worked as a librarian. Hours later, he said he opened the bedroom closet and found her body inside.
After calling 911, Johnson was interrogated by Arlington police for several days. He did not request an attorney. He told "20/20" that detectives were aggressive and yelled in his face that he murdered his fiancée.
At one point a detective told Johnson that Cincotta was alive after he came home and that his fingerprints were found on her. After the interrogation, Johnson learned that that was a lie.
"I was in shock. How can they get away with it? How can they do that?," Johnson said. "You trust the police, the police don't lie….I literally had no reason to believe that they're lying to me."
After 25 hours of questioning over several days, Johnson said he was exhausted and began to tell officers a "dream vision" of how he imagined arguing and hurting his fiancée. He wrote down his vision and didn't ask for an attorney.
"If you had gone through what I went through for as long as I went through it and you had just found the woman you love dead, you're not in a good place," Johnson said.
It turns out, the details Johnson had provided in his supposed admission do not match the autopsy results - she had died from strangulation – not a blow to the head
Arlington Police released Johnson and did not charge him at the time.
Cincotta's son Kevin, who was 24 at the time, did provide investigators with a key clue. He remembered that his mother told him that she gave her computer to a man who was working at her apartment complex.
Johnson had also told police about the man, telling them "it was not like her to talk with a perfect stranger – especially to allow him in the apartment."
Although Kevin Cincotta didn't know the man's name, investigators were able to identify the person as Bobby Joe Leonard. Leonard was in a Philadelphia jail after being arrested for allegedly assaulting his wife.
The charges were later dropped.
Virginia investigators questioned Leonard in jail, and took his DNA and fingerprints. He denied murdering Cincotta and his DNA and fingerprints weren't be found in the home.
Johnson's attorney Frank Salvato alleged at Johnson's trial that investigators' handling of the crime scene compromised the touch DNA found on Cincotta's throat so it could not be tested.
The prosecutors said detectives could have done a better job processing the crime scene, but they insisted that this case wasn’t about the crime scene, it was about Johnson hiring Leonard to kill Cincotta.
Leonard would be arrested a year later on rape, abduction and attempted murder charges in Fairfax for brutally attacking a 13-year-old girl and leaving her for dead in a closet. He was convicted in 2000 and sentenced to life in prison.
Around the same time, Johnson met Ginnie Grevett and the two would eventually marry. In an exclusive interview, Grevett told ABC News that Johnson told her about the murder investigation on their first date.
"I accepted it 100%," she said of Johnson's denial of murdering his fiancée. "It never occurred to me ever that he might have had anything to do with it whatsoever."
Johnson said Kevin Cincotta accepted his assurances that he had nothing to do with Andrea Cincotta's murder and they initially remained friends. But the two drifted apart and rarely spoke until 2018 when Kevin Cincotta asked to get together for lunch.
Johnson didn't know that Kevin Cincotta now suspected that he might be involved in his mother's death, and was working with investigators on the cold case.
In an attempt to catch Chris saying something incriminating, Kevin was wearing a wire.
During the lunch, Kevin tells Chris that he has seen the police file and now has a different take on the case. Kevin told Chris that he believed Chris killed his mother.
Chris Johnson told "20/20, "I was really hurt. I was like, I wonder if he was wearing a wire because of the way he was asking the questions and everything like that."
That same year, investigators caught a break after Leonard claimed to have found God and confessed to the murder of Andrea Cincotta and made a shocking new allegation.
He told detectives that he strangled the librarian to death in her apartment, but he also alleged that he received a call and a $5,000 offer from an unnamed man who he believed to be Cincotta's boyfriend to commit the crime.
Officers and prosecutors would use his allegations to charge Johnson with murder for hire in 2021. Johnson denied being involved or contacting Leonard.
"I was just like, it's ridiculous. I was racking my brain. How in the world did they come up with this?" Johnson said.
During the trial, prosecutors brought up Johnson's "dream vision" statement during his original questioning in 1998. They also put Leonard on the stand who testified in detail about how he killed Cincotta.
Salvato, who represented Johnson at trial along with Libbey Van Pelt and Manuel Leiva, noted that Leonard wouldn't take the stand until prosecutors agreed to put a request into the Virginia Dept of Corrections to have him moved to a different, lower-security prison.
During cross-examination, Salvato questioned Leonard's story that he knew that Andrea Cincotta's boyfriend was the man who called him about arranging the murder because he recognized her number on his landline's caller ID.
The defense brought in Leonard's ex-wife Frances Hudson who testified that their landline phone did not have caller ID when they lived together. She testified that she moved out of their home weeks before the murder after Leonard assaulted her.
Prosecutors admitted there was no forensic evidence tying Leonard and Johnson to the alleged murder-for-hire plot, claiming it was because too much time had passed to collect phone records and other verifying information.
Salvato pointed out an inconsistency in Leonard's testimony: he said that Cincotta didn't struggle when he attacked her, but the autopsy showed signs of bruising on Cincotta consistent with someone fighting back.
When the case was presented to the jury in October, it took just one hour to reach a verdict. Johnson and his attorneys were shocked by the speedy result.
"They gave it to the clerk. The clerk said, 'Not guilty,'" Johnson said. "It was a relief."
Salvato claimed in a "20/20" interview after the verdict that he believed Johnson should never have been brought to trial.
"As he has said from day one," Salvato said, "he had nothing to do with Andrea Cincotta's death."
Two members of the jury spoke with "20/20" about their decision and said there was a lot of doubt in the prosecution's case.
"You don't hire someone to kill someone whom you've never met," jury forewoman Chen Ling told "20/20. "And, out of all the Bobby Joe Leonard testimony, he never claimed that they met. I feel like that was, for me, the important detail that gave reasonable doubt."
Another juror told "20/20" he questioned the tactics used during the interrogation with Johnson.
"It seemed to me that the police were just hammering home what they thought to be the case. They weren't taking his initial statements for face value. So it was pushing him to get to another answer," the juror said.
Kevin Cincotta, who testified against Johnson during the trial, declined to sit down for an on-camera interview with ABC News in time for air. He provided ABC News with a detailed account of the reasons he is still convinced Johnson is guilty of murder for hire.
Some of the reasons included what he calls suspicious behavior and alleged discrepancies in Johnson's story and information he believes Bobby Joe Leonard could only have received from Johnson.
Kevin Cincotta added he doesn't forgive Leonard, who was issued an additional life sentence for Cincotta's murder, but believes his allegations against Johnson.
The Arlington County Police Department declined to comment to ABC News on the criticisms raised by Johnson and his attorneys.
The Commonwealth's Attorney of Arlington County said in an email to ABC News, "We hope that through the process we have helped bring some closure to Ms. Cincotta's family. However, I must respect the verdict of the jury. We prosecuted a tough case in the fairest way we could, and that's where I believe I should leave it."
Although Johnson is currently free from prosecution, he said that he is forever changed by the experience.
"Something like this... You're never going to be the same," he said. "I used to be a lot more trusting. I trusted everyone, trusted the police, and now my eyes have been opened."