Most notably, Slepian is known for his in-depth reporting about the criminal legal system and specifically, wrongful convictions. His documentaries on the topic have earned him a total of 14 Emmy nominations. 

In February 2023, NBC News released “Letters From Sing Sing,” an eight-episode podcast hosted by Slepian that documents his 20-year journey investigating the wrongful conviction of JJ Velazquez. The podcast hit #1 on Apple’s top charts the day of its release.In May 2022, The New York Times published its second feature about Slepian, detailing his 20 years of reporting that helped exonerate six innocent men. His debut book, The Sing Sing Files: One Journalist, Six Innocent Men, and a Twenty-Year fight for Justice will be released in September 2024.

Slepian also conceived, developed and produced Justice For All, an NBC News/MSNBC week-long event that included the Emmy nominated first town hall from a maximum security prison as well as Dateline’s Emmy nominated Life Inside, an impactful and emotional hour about mass incarceration in which Slepian and anchor Lester Holt spent two nights inside Louisiana’s notorious Angola prison.

In February 2021, NBC premiered Dateline’s first docuseries, The Widower, an epic five-hour network primetime series detailing Slepian’s 13-year investigation into an eccentric murder suspect who’d been married six times, and four of his wives are dead.

In May 2019, Dateline debuted its first-ever podcast with Slepian at its helm. The eight-episode series “13 Alibis” chronicles Slepian’s investigation into a confounding murder case and helped exonerate an innocent man. In 2018, Slepian was granted exclusive access to film rapper Meek Mill on the day of his highly publicized release from prison. Dateline's special, Dreams and Nightmares featured Lester Holt's exclusive interview with Meek just hours after his release. 

As a volunteer, Slepian works with incarcerated men at Sing Sing prison where he helped create "Voices from Within," a video featuring deeply personal testimonials intended to help reduce gun violence. Slepian introduced the project during a TEDx talk at Sing Sing. Before joining NBC News, Slepian began his career with the Phil Donahue talk show. Read Less ^