“So what is it that we do?” says Mr. Phillips. “We deal in the commodity of hope. Don’t quit. Don’t stop. Keep the hope alive.”

Criminal convictions are purposefully difficult to overturn, and especially difficult when there’s no DNA evidence. The procedural barriers just to reopen a case are almost endless.

It is the tantalizing prospect of uncovering new information that might free other innocent men that drives them. They visit clients in prison and track down potential eyewitnesses. They meet with prosecutors and lawyers. Their Dallas-based nonprofit, House of Renewed Hope, also campaigns for criminal justice reforms and raises awareness about how the system often fails.

The reason they do this work is simple: Mr. Scott and Mr. Phillips spent a combined 37 years in prison for crimes for which they were eventually exonerated. That’s why they read every letter they receive.

There’s a lot of waiting and a lot of failure in this line of work. It starts with emptying a North Texas P.O. box full of mail from prisons across the country. And for the letter writers who persuade Christopher Scott and Steven Phillips to take their cases, the hope is that it ends with a wrongfully convicted person walking free.

The busiest P.O. box in North Texas may be in a drab, beige hallway in the post office of this Dallas suburb. Box 2075 is not stuffed with grocery coupons or credit-card promotions. It’s full of letters, mostly handwritten and postmarked from prisons across the country, addressed to what may be the most unusual detective agency in America.

This agency doesn’t have an office with a frosted glass window. Nor do the detectives snoop on cheating spouses or deadbeat debtors. The letters that pile up are from prisoners or their family members, pleading for help in overturning criminal convictions. All say they were wrongfully imprisoned.

The man who empties the box is Christopher Scott. Broad-shouldered and barrel-chested, he dresses sharp, talks in the gritty patois of the South Dallas neighborhood he grew up in, and uses his bright smile sparingly.

Under normal circumstances, he probably wouldn’t know Steven Phillips, and they most likely wouldn’t be best friends or partners in a detective agency. They’re from different backgrounds and different generations. While Mr. Scott navigated urban streets as a youth, Mr. Phillips grew up in the country, in the Ozarks, and has the drawl to prove it. He takes his wardrobe and most other things less seriously than Mr. Scott. A lifetime of fistfights has cost Mr. Phillips several teeth, but he cracks jokes and smiles energetically, and often. Mr. Phillips is older, as evident from his salt-and-pepper stubble, but it is Mr. Scott who is the grandfather.

Yet for all their differences, these two men – one white and one African American – have forged a common bond around a common purpose: trying to get people out of prison who should never have been there in the first place. Their Dallas-based nonprofit, House of Renewed Hope, also campaigns for criminal justice reforms and raises public awareness about how the system often fails.

But it is the tantalizing prospect of uncovering new information that might, just might, free other innocent men that drives Mr. Scott and Mr. Phillips the most. They spend their days meeting clients in prison, tracking down and interviewing family members, friends, and potential eyewitnesses. They meet with prosecutors and activists, lawyers and experts.

There’s a lot of waiting, too. Waiting for court rulings, for district attorneys to reply, for inmates to write back. And there’s a lot of failure, the cases that don’t crack, however much you want them to.

Criminal convictions are purposefully difficult to overturn, and especially difficult when there’s no DNA evidence to present to a judge. The procedural barriers just to reopen a case are almost endless. “It’s harder now to get somebody exonerated than ever, man,” says Mr. Scott.

He should know. As should his partner.

The reason Mr. Scott and Mr. Phillips do this work is simple: The two men spent a combined 37 years in prison for crimes they didn’t commit, crimes for which they were eventually exonerated. That’s why they read every letter they receive. They know there are others like them behind bars. Others desperate for someone to help prove their innocence.

“We couldn’t begin to investigate all the cases we get sent to the mailbox, man,” says Mr. Phillips. “So what is it that we do? We deal in the commodity of hope. Don’t quit. Don’t stop. Keep the hope alive.”

“Not too scared”

It’s a cold, wet October day in Dallas – 10 years to the day since Mr. Scott became a free man. He has the same bulky build as when he left prison, and he’s dressed as sharply as he was before he went in. But his neatly trimmed beard is flecked with gray and white.

“We was wronged,” he says. “If you don’t want to see this happen to a lot of other people, there’s things that we can do, because we’ve been a part of that system before.”

Ann Hermes/Staff Christopher Scott shuffles through mail at a post office in Coppell, Texas. His Dallas-based nonprofit, House of Renewed Hope, reads every letter from prison inmates and family members who ask for help with their cases.

Raised by a single mother, and the youngest of nine siblings, Mr. Scott learned responsibility early on. He got his first job at age 17 at a burger joint. Within a few years, he was a produce manager in a grocery store, raising two kids and driving a Lexus.

One April night in 1997 he was riding around his neighborhood with a friend, Claude Simmons. On their way home, he noticed a heavy police presence in the area and a helicopter flying overhead. A familiar nervousness crept in. Hours later Mr. Scott and Mr. Simmons were arrested along with dozens of other African American men who fit the descriptions of two suspects in a nearby homicide.

He was handcuffed and taken to a police station downtown, but he knew he hadn’t done anything wrong. “So I’m scared, but I’m not too scared,” he recalls. “In my head I’m thinking the law, the justice system, is going to get it together and figure it out.”

Instead, he was identified by the wife of the slain man as one of the attackers. She had been sexually assaulted and her husband shot dead during a home invasion.

No physical evidence linked him to the crime, and her testimony was crucial in convicting Mr. Scott in a trial that lasted only four hours. An all-white jury sentenced him to life in prison. (Mr. Simmons was tried separately and convicted for the same crime.) Mr. Scott was 27 years old, weighed just 130 pounds, and was headed to Coffield, a notorious state prison.

Life sentence

Routine is key to surviving and finding purpose in prison, and he soon found his. He labored in the prison fields and worked out in the yard, putting on 100 pounds of muscle. He read three books a week, including law tomes, looking for ways to prove his innocence. He compared notes and exchanged tips with other guys in Coffield filing innocence claims in courts.

His break came when a group of law students at the University of Texas at Arlington discovered that two other men, one of whom was in prison for aggravated robbery, had committed the murder for which Mr. Scott had been convicted. The prisoner confessed, and in 2009 his accomplice was arrested in Houston.

After Mr. Scott passed a six-hour polygraph test, he was exonerated; Mr. Simmons was also exonerated. The two men were brought before a judge in Dallas and declared innocent.

“I couldn’t do nothing but shake my head,” Mr. Scott says. “I was like, ‘Dude, I asked for this 13 years ago, and they didn’t give it to me.’

“But I was happy. I knew I was going free. It was over.”

When Mr. Scott got out, Mr. Phillips was waiting for him. He was in the courtroom for the exoneration hearing. Afterward he introduced himself and told him to call if he ever needed anything. Mr. Scott was wary at first – with everything he’d been through, he says, he didn’t trust white people – but after a few days living with his mother he did call.

Mr. Phillips let him stay at an apartment he owned, lent him some money, and even bought him a cheap car.

Advocacy and tenacity

A year later, after going to regular meetings with other exonerees, Mr. Scott set up the House of Renewed Hope using some of his compensation money from the state. (Texas awards exonerees $80,000 for every year they were wrongly imprisoned, as well as monthly annuity payments if they’re eligible.) That compensation, along with some donations and payments to Mr. Scott for speaking engagements, fund the group. He asked Mr. Phillips and Johnnie Lindsey, another exoneree, to be co-founders.

Mr. Lindsey died in 2018, but today eight employees – a mix of paid staff, including a lawyer, and volunteers – keep the organization running. Together they have built an agency that is respected, both for its advocacy work and its tenacity in investigating cold cases, by others who have a stake in the criminal justice reform movement in Texas.

“To have gone through what he went through and still be able to come out and say, ‘I’m going to help somebody else who might be in the situation I was in,’ is admirable,” says Cynthia Garza, head of the Dallas County district attorney’s conviction integrity unit. Her first case after joining the unit was Mr. Scott’s exoneration. He and Mr. Phillips, she says, “have a different perspective that they bring to these cases.”

Both bring their own talents and experiences to the enterprise. Mr. Scott is the president, public face, and driving force behind the group. But it’s Mr. Phillips who has a facility with the law and knows how to prepare a writ. He honed his legal skills in the same place Mr. Scott did: the Coffield prison law library. And like Mr. Scott, miscarriages of justice took him there.

Ann Hermes/Staff Exonerees Christopher Scott and Steven Phillips were held in Texas’ Coffield prison. Both men read law textbooks while incarcerated, looking for ways to prove their innocence.

He was working as a roofer in Dallas in 1982 when a woman reported an armed man had broken into her apartment and raped her, one of a string of sex crimes committed in the area. She later identified Mr. Phillips as her assailant, as did other victims.

He had an alibi for that day, and there was no physical evidence tying him to the assault. But he was convicted of rape and burglary in two separate trials and sentenced to concurrent 30-year sentences.

Law library reading

Like Mr. Scott, Mr. Phillips was sent first to Coffield. As a teen in Arkansas, before he enlisted in the U.S. Army and served in Germany, he had learned to box, and his left jab-right hook combo helped protect him within the Darwinian walls of prison. He made the prison basketball and softball teams. But mostly he hit the books in the law library, filing all the post-conviction motions he could, to no avail.

His case appeared hopeless. Every day he prayed, asking God to help him show that he was innocent. Years later his prayer changed. If God wanted him exonerated, God was going to have to do it. Mr. Phillips shoved his typewriter under his bunk and resolved to never file another motion.

Then everything changed.

In 2006, the Innocence Project in New York took up his case and secured evidence that proved his innocence. The Dallas County district attorney linked DNA from the crime scene to a felon who had died in prison in 1998 after being convicted of 16 other sexual assaults and related crimes, and cleared Mr. Phillips of all charges. On Oct. 1, 2008, he was a free man again.

“Faith carried me all the way – until science took over,” he says.

Transformation of DNA

Science, he thinks – DNA testing in particular – has transformed criminal justice in the United States. It’s “a little disagreement” he has with Mr. Scott, who still harbors a deep mistrust of the system.

“I say the system is better now than it was 20 or 25 years ago,” Mr. Phillips says. “It’s not perfect at all, but the science is improving, and the science is holding [people] to at least try for a more perfect system.”

Indeed, DNA science has been pivotal in exploding the long-held myth that wrongful convictions are rare. The first man to be exonerated by DNA evidence was Gary Dotson in 1989. Since then, more than 2,500 people have been exonerated in what has become known as the innocence movement.

Still, for every release of a wrongfully imprisoned person, many others may remain behind bars because there’s not enough evidence to persuade authorities to reopen their cases, experts say. “It takes a tremendous amount of evidence, legal work, and just plain luck to be able to exonerate someone,” says Keith Findley, an associate professor at the University of Wisconsin Law School and co-founder of the Wisconsin Innocence Project.

Jim Mahoney/The Dallas Morning News/AP/File James Lee Woodard (center) celebrates his exoneration outside a Dallas court April 29, 2008, with Jeff Blackburn of the Texas Innocence Project (left) and Assistant Public Defender Michelle Moore. Mr. Woodard is one of about 2,500 people who have been exonerated in the U.S. since 1989.

He and other legal experts believe that the justice system’s reliance on DNA – the science that spelled salvation for Mr. Phillips and launched the innocence movement – has now become a handicap. DNA tests provide an ironclad proof of innocence. But most cases don’t have any biological evidence to test, and ironclad proof has become almost mandatory.

When Mr. Phillips brings a case to a district attorney, he says, the first question is usually, “Is there DNA?” “If there’s not DNA, and just, [say], some question of misidentification involved, they may not [reopen] that case,” he says.

A hierarchy of innocence now exists, says Daniel Medwed, a professor at Northeastern University School of Law in Boston. “It’s made it harder to prevail in non-DNA cases.”

Absent DNA, Mr. Phillips and Mr. Scott need to uncover other physical evidence that was overlooked or unlawfully suppressed that could have changed the jury’s decision. They need to unearth new eyewitnesses or, better yet, a confession from another suspect. Even then, claims of “actual innocence” – the legal standard for exoneration – in Texas have to be approved first by a trial court judge and then by the Texas Court of Criminal Appeals.

“Texas is very challenging in that regard, but it’s also a blessing,” says Ms. Garza. You “don’t water down what actual innocence means. You can’t hand [exonerations] out like candy.”

“The bar is so high”

While there are likely a lot of innocent people in prison who can’t find enough evidence to prove it in court, there are also a lot of people making frivolous post-conviction appeals. It’s in this area that Coffield has given Mr. Scott a sixth sense of who is believable.

“In prison you automatically become an investigator,” he says. “In a 5,000-man unit, I heard different stories every day. So my thing was [to] break it down and make sense of what I think they’re telling me.”

Even the strong cases are time-consuming and tedious. House of Renewed Hope is working on a half-dozen cases at any one time, but in nine years it has only come close to helping to exonerate a few clients. In one case, the investigators tracked down a man who admitted to committing a robbery for which their client, Isaiah Hill, had been convicted, but the man refused to testify formally. Mr. Hill was released on parole in 2016 after 40 years in prison.

Mr. Phillips is sure of his innocence, but knows that an exoneration – and the compensation money that Mr. Hill is desperate for – is out of reach. “The bar is so high. You have to have overwhelming evidence in your favor to get back in court. ... He didn’t reach that bar, and that’s just unfortunate,” he says.

Given all the difficulties, the mix of prison-yard smarts and investigative grit that Mr. Scott and Mr. Phillips bring to a case can be a boon to lawyers working on potential exonerations.

“Ultimately [exonerations] come down to good lawyers doing good work,” says Mike Ware, executive director of the Innocence Project of Texas. “But I think what good lawyers doing good work need is sometimes the raw tools and raw information to work with, and I think sometimes exonerees can help with those raw tools and raw information.”

Changing the system

Working for House of Renewed Hope, though, means pursuing more than just exonerations. It also means trying to prevent wrongful convictions in the first place.

On that rainy day last October, Mr. Scott drives to Friendship-West Baptist Church in South Dallas to join a panel discussion on issues facing African American men. A small audience sits in the front pews of the cavernous church, greeting friends and shaking off rain-soaked umbrellas.

It’s just weeks after former Dallas police officer Amber Guyger was convicted of murdering Botham Jean, a young black man, while off duty, and the first question, perhaps unsurprisingly, is about police brutality and the fairness of the criminal justice system. Daryl Washington, a prominent local lawyer who represented the Jean family, talks about the importance of involving the black community in all aspects of law enforcement and the court system. Without five black jurors, he says, Ms. Guyger would have walked.

Mr. Scott picks up his cue. “I had an all-white jury, judge, prosecutor, and defense attorney,” he tells the audience. “We’ve got to vote for change. We’ve got to get the right people in office” as judges and prosecutors.

House of Renewed Hope staff rarely all meet together, instead working out of their own homes or offices. This flexibility leaves time for personal commitments, which for people who spent years locked away from their families are very important.

The next day Mr. Scott picks up his grandson from school to take him to a barber shop for his weekly haircut. In prison, he missed most of his two sons’ school years, and he is now a doting grandfather. The 6-year-old, who was nodding off in the car, falls asleep in the barber’s chair, so Mr. Scott holds his head up while talking sports with the room. “Every Friday I’m holding his head up,” he says, smiling.

It’s more than his grandson’s head that he’s holding up. He’s holding up the hopes of every person who sends a letter to P.O. Box 2075.

He’s getting close with one case. House of Renewed Hope has teamed up with the Innocence Project of Texas to try to exonerate Leslie Davis, a man who served 28 years in prison for aggravated robbery. His conviction was based largely off testimony from a Dallas police officer who claimed he’d eavesdropped on Mr. Davis confessing to the crime while hiding in some bushes.

Some other Dallas officers gave similar testimony around that time in the early- and mid-90s, earning the nickname the “Bushmen” with some county prosecutors, and it later came to light that several of them had been disciplined internally for dishonesty.

“That’s something that should have been disclosed to the defense and was not,” says Mr. Ware of the Innocence Project of Texas.

Mr. Davis was released on parole several months ago, but he is still trying to clear his name. “It’s close,” says Mr. Scott. “We just need a little more information.”

Until then, Mr. Davis must wait, and wait. That’s something that exonerees know only too well, that feeling of being stuck, of a stolen life fading away.

“I can relate to that,” says Mr. Phillips. “And I’d like to help them if I can.”

Editors note: This story was clarified on March 3 to more accurately reflect House of Renewed Hope's previous cases.