In December of 2002, NBC News producer Dan Slepian got a letter from a New York state prison. It was detailed and meticulous, almost like it had been written by a lawyer. But it wasn’t. It was from a man serving 25 years to life for murder. And it ended with a desperate plea: look into my case.

Jon-Adrian “JJ” Velazquez had been convicted of killing a retired New York City police officer, but he insisted he didn’t do it. Dan was skeptical. Prosecutors said five eyewitnesses had sworn JJ was the killer. Could five people be wrong?

But JJ was adamant about his innocence. He had devoted years to fighting his case, spending hours in the law library, poring over every page of his file. He was confident that if Dan looked into it, he’d see the truth. He even challenged Dan to prove him guilty.

So Dan began to dig. What he discovered went far beyond just JJ’s case. And 20 years later, it’s still unfolding.

Letters from Sing Sing tells the story of a man convicted of murder, a journalist, and the letter that changed both of their lives. New episodes drop every Monday through March 27, 2023.

In December of 2002, NBC News Producer Dan Slepian got a letter from a New York State maximum security prison. It was detailed and meticulous, almost like it had been written by a lawyer. It was from a man serving 25 years to life for murder. And it ended with a desperate plea: look into my case.

In 1998, Jon-Adrian “JJ” Velazquez was arrested for killing a retired New York City police officer. A year later, he was convicted of second degree murder. But he insisted he didn’t do it. Dan was skeptical. Prosecutors said five eyewitnesses had sworn JJ was the killer. Could five people be wrong?

So Dan pays JJ a visit. And at the end of it, JJ gives Dan a challenge: prove me guilty.

JJ Velazquez claimed he had an alibi: a 74-minute phone call on a landline with his mother, Maria Velazquez, that overlapped with the time of the crime. So Dan visits Maria. She lives in a town in New York on the Hudson River directly across from Sing Sing, the maximum security prison where her son is incarcerated. Maria talks to Dan about JJ’s childhood. And she recounts in detail her memory of January 27th, 1998, the day of Al Ward’s murder.

Meanwhile, Dan is still familiarizing himself with JJ’s case file. There are thousands of pages of documents that sit in a box by his desk. He starts to work his way through the trial transcript. Immediately, it’s clear to him that the trial was strange. As Dan unpacks what happened in the courtroom, he’s left with more questions than answers. Prosecutors say five people identified JJ as the man who killed Al Ward. Dan decides to find them.

It turns out, back in 1998, just days after the crime, the NYPD had a main suspect for the murder of Al Ward: a man named Mustafa. Dan tries to find out more about Mustafa and understand why this lead was dropped after JJ’s name entered the case. He also learns that JJ’s legal team had a court-assigned private investigator. Dan tracks down that private investigator, and discovers that he hardly looked into JJ’s case. He didn’t know about Mustafa and he never interviewed the eyewitnesses to the murder of Al Ward.

So Dan decides to do what the private investigator didn’t do – investigate JJ’s case. In the summer of 2009, Dan finds Augustus Brown, the key witness, the man who first identified JJ. He’s incarcerated at the Elmira Correctional Facility in upstate New York. Dan pays him a visit.

Dan tracks down Juror Number Six: Ramon Aviles. Ramon remembers the moment when the 84-year-old eyewitness, Dorothy Canady, pointed him out as the shooter. He says he was shocked and that people were laughing. The juror breaks down what he remembers from the deliberation room and ultimately admits he might have made a mistake in voting to convict JJ.

Dan starts to wonder if other jurors from JJ’s trial would feel the same way. He meets up with a different juror and when she sees Dan, she immediately starts to cry. She says she felt pressured by some of the other jurors to convict JJ because they were sequestered and wanted to go home. More than decade later, she believes she ruined JJ’s life.

Dan is stunned. He’s building a compelling case for JJ’s innocence, but there’s still one more person he needs to talk to: JJ’s alleged accomplice, the man with the duct tape, Derry Daniels. Dan visits Daniels, who refuses to talk to him, but Dan is now certain that JJ did not get a fair trial. He sits down with Barry Scheck, co-founder of the Innocence Project, to talk through the case. Barry explains how eyewitness accounts can be unreliable.

It’s been eight months since Dan’s investigation into JJ’s case aired on Dateline. When he visits JJ at Sing Sing, JJ is frustrated—he thought he’d be out by now. But the Manhattan DA is looking into his case. In 2010, Manhattan DA Cyrus Vance created a conviction integrity unit focused on investigating claims of innocence. Bob Gottlieb and Celia Gordon, JJ’s lawyers, are confident that this unit will determine that he was wrongfully convicted.

Meanwhile, Bob and Celia hear from a woman who claims she and a friend know Mustafa: the NYPD’s “primary target” for the murder of Al Ward. Dan follows up on this lead and travels to Seattle, where he interviews both women. They tell him their friend Mustafa confessed to killing Al Ward. Dan tracks down this Mustafa, and in a tense interview, tries to determine whether this man is the real killer.

By 2015, JJ had been locked up for nearly 18 years. His mom, Maria, drives to Sing Sing to visit him on his 40th birthday and reflects on how much it hurts to watch him age in prison.

In the last decade, JJ has built a rich life in prison in order to survive. He talks about his involvement in the prison’s programs, like organizing fundraisers and leading workshops. He was even elected by the prison’s population to speak for them when issues came up. He says this work has given him purpose, but it also helps distract him from the trauma of being incarcerated for a crime he didn’t commit.

While all of this is happening, JJ’s older son, Jon, gets into more trouble. He’s arrested on charges of burglary. He hides out in a motel room, and Dan goes to check on him there.

Dan also follows up on old and new leads in JJ’s case. And then one day, he gets a yellow envelope in the mail.

In 2017, JJ finally gets some good news. After years of denials and setbacks, he would appear before a judge for the first time since his conviction. A new judge would determine whether JJ’s rights were violated when the prosecutor at his trial withheld police reports related to his case – reports that, 10 months earlier, had arrived in Dan’s mailbox.

But the judge ultimately denies JJ’s request for a new trial. Dan and JJ are devastated. JJ explores other avenues for getting released. He applies for clemency, but year after year, the governor passes him over. Then, in 2020, the pandemic hits. The world stops. And JJ experiences the pandemic behind bars.