On Sunday, February 12th at 7pm/6c, NBC News' Luke Russert tells the story of Jon-Adrian Velazquez, convicted of murdering a retired NYPD officer back in 1998. An investigation that the Dateline team has been working on for 10 years, Russert interviews Velazquez, his mother, former girlfriend, sons, eyewitnesses and attorneys. They also recount the timeline - asking the question – is Velazquez, who is serving 25 years to life in Sing Sing Correctional Facility, actually innocent?

Dateline frequently receives mail from prison inmates making claims of innocence. Many of those claims turn out to be unfounded. But almost ten years ago, when Dan Slepian, a Dateline producer, began receiving letters from Jon-Adrian Velazquez, there was something in his story that seemed to warrant a careful re-evaluation of his conviction. This case then attracted attorneys Celia Gordon and Bob Gottlieb who have been representing Velazquez for the past two years and who believe they now have enough evidence to prove that he is an innocent man.

Also on Dateline Sunday, after Jack Jessee was killed in his Orange County home in 1998, the trail went cold until Detective Tom Dove's investigative prowess led to putting Jessee's wife and her hired hitman on trial. 'Deadly Conspiracy' is part of Dateline Sunday, February 12, at 7pm/6c.