Keith Mitchell, center, and Gary Gathers, right, are photographed with Mitchell's attorney, Andrew Wise, left, during an interview. (Ricky Carioti/The Washington Post)

It was the strangest thing for Keith Mitchell. Weeks after his recent release from 21 years and 129 days in prison, Mitchell stood in front of a sink in a public restroom, bewildered.

Mitchell didn’t realize that the sinks were operated by motion sensors. He had the same problem with toilets. And the automatic self-checkout stands at the grocery stores required some hand-holding from a nearby cashier.

“Everything has changed so much,” the 40-year-old Mitchell said.

His childhood friend, Gary Gathers, 39, spent more than two decades in prison for the same crime. Sitting next to Mitchell at his mother’s apartment, he laughed in agreement. He feels the same way.

“These tiny cellphones, automated toilets — man, everything is different, ” Gathers said.

Gary Gathers, left, and Keith Mitchell. (Ricky Carioti/The Washington Post)

Indeed, the world has changed since 1993, when the two men were arrested, found guilty of first-degree murder and sentenced to a minimum of 35 years to life in prison for the fatal shooting of a D.C. man, a death in which the men always said they were not involved.

In April, six months after the D.C. Court of Appeals overturned their convictions and ordered a new trial in the case, prosecutors told a D.C. Superior Court judge that they were dismissing the case.

Prosecutors still say that the men are guilty but that after 20 years they no longer have enough evidence to secure a conviction in a second trial.

Although not as publicized, overturned convictions in cases that do not rely on DNA evidence — like those of Gathers and Mitchell — occur more frequently than cases reliant on DNA, according to the Mid-Atlantic Innocence Project, which works to overturn wrongful convictions. Since 2010, the group has helped free 11 people that attorneys thought were innocent in the Washington region. Of those cases, six did not involve DNA, four had DNA as evidence, and one used both DNA and witness testimony. The cases involving DNA evidence more often result in exonerations, said the group’s executive director, Shawn Armbrust.

Cases without DNA evidence are often more difficult to prove in court, Armbrust says, largely because they are circumstantial: Prosecutors and judges have to be convinced that new evidence and witness testimony is truthful and relevant to warrant an exoneration or dismissal. Those cases that have DNA evidence can use science to overturn a wrongful conviction.

Although Gathers and Mitchell were not exonerated, Armbrust said she still considers their overturned murder convictions a “victory.”

In the Gathers and Mitchell case, Armbrust said she believed the men were innocent because of problems with the first trial and because another suspect should have been identified as the shooter.

“That weak case has crumbled, and the evidence pointing to another perpetrator proves their innocence,” Armbrust said.

Exoneration or not, the men and their attorneys, consider the dismissal a justified win.

Gathers and Mitchell, who now spend their days working for landscaping companies, had maintained their innocence during their entire prison stay, researching the law and fining avenues where they could get their pleas heard.

“My mother knows I didn’t do it. My girlfriend knows I didn’t do. I’m good,” Gathers said.

“We don’t have to prove anything to anybody,” Mitchell added.

Prior to their arrests in the case, both men had brushes with the criminal justice system when they were teenagers. Gathers, as a youth, was arrested and spent some time in a juvenile shelter.

But Mitchell had been charged in a murder case just two years earlier when he was 17. That case ended up being dismissed because the judge overseeing the trial did not find any evidence linking Mitchell to the death.

“I’m not saying I was an angel growing up, but I didn’t do these crimes they put on me,” Mitchell said, adding that he was not involved in the man’s death. “In my neighborhood then, when something happened, the police came and grabbed everybody up.”

A year after prosecutors dismissed the case, Mitchell was arrested again, along with Gathers, in the 1993 murder of Wayne Ballard, 23. “I couldn’t believe this happened again,” he said.

At the trial in 1994, prosecutors argued that Gathers and Mitchell had learned that Ballard was going to be a witness in another case. The prosecutor and a lead detective said that Ballard’s name was mentioned in court as a cooperating witness, leaving Gathers and Mitchell with the opportunity to target him.

In October, the appellate judges ruled that the primary motive, which prosecutors said was behind Gathers’s and Mitchell’s motivation to kill Ballard, never occurred. The judges determined that Ballard’s name was never mentioned in open court and that the prosecutor and lead detective mistakenly relayed that information to the jury as the primary motive for the two men in Ballard’s killing.

So in an unusual decision, the court ruled that the two men were convicted on “false evidence” and ordered a new trial.

Even before the appellate judges’ ruling, the men petitioned for a new trial after learning that the lead witness in the case, who identified the men as the shooters, had later recanted his story. The men also learned that prosecutors at the time failed to turn over a key piece of information: that Ballard’s life had been threatened by members of his own gang because Ballard had seen them participate in an unrelated shooting.

Members of Ballard’s family did not return repeated calls seeking comment about the dismissal.

“I am sorry for their loss,” Gathers said. “But I didn’t have anything to do with Mr. Ballard being murdered.”

While behind bars, life outside continued. Mitchell’s daughter was an infant when he was locked up, but now she’s an adult. Gathers never got a chance to have children, but he missed out on the funeral of his grandmother, who helped raise him.

Both men, who have been friends since childhood, found their own path to surviving in prison. Mitchell, who was raised as a Christian, converted to the Muslim faith, which he said offered him a sense of security.

Gathers focused on his education. He earned his GED and spent days poring through legal books in prison libraries. Gathers learned about filing appeals and began writing hundreds of letters to defense lawyers and law schools.

“I targeted everyone I could to get out,” Gathers said. He rarely received a reply, and when he did, the lawyers said only that they could not take the case.

Eventually, one attorney took the case and then handed it to the Innocence Project, which identified lawyers, who after reviewing the details of the case, volunteered to take it over. In all, seven lawyers worked on the appeal.

Gathers’s attorney, Seth Rosenthal, said that the men never gave up hope and were encouraged to keep fighting. “We ran into a lot of hurdles along the way, but they never lost their optimism, and that encouraged us,” Rosenthal said.

“It takes a lot of faith and confidence to continue to fight and never let setbacks bring them down,” added Andrew Wise, Mitchell’s attorney.

Mitchell, who has struggled with a learning disability, plans on getting his GED and later starting a nonprofit that works with youths. Gathers would like a job driving for Metro.

“I am just so grateful to be home,” Mitchell says. He and Gathers shower their attorneys with praise for believing in them.

Court records now show the case as closed. The men say that they hope to one day be exonerated. But the people most important to them know they are innocent, and for now, that’s good enough.

Jennifer Jenkins contributed to this report.