On October 2, 2002, an innocent man was shot dead outside a bustling supermarket near Washington, D.C. Though police ruled it an isolated attack, it proved to be only the first in a series of 13 shootings that would terrorize the area in weeks to come. On September 6, MSNBC Films will bring viewers the inside story on the men behind it all, ‘D.C. snipers’ John Allen Muhammad and Lee Boyd Malvo. Interviews with Muhammad’s ex-wife Mildred—who had divorced him long before the attacks—tell of her former husband’s transformation from a happy father of three into a cold-blooded killer—who marked her as his final target. The 2-hour special, “I Married The Beltway Sniper,” premieres at 10 PM ET.

Nearly eight years after the attacks and almost one year since Muhammad’s execution, questions still remain: What was Muhammad’s motive for the attacks? Was Lee Boyd Malvo a ruthless killer, or a brainwashed child in a cult of only two members? Using Malvo’s trial testimony, archived news footage and rare audio recordings of the snipers in their own words, MSNBC Films will uncover what drove this deadly duo to murder so many innocent people.

“I Married The Beltway Sniper” features in-depth interviews with individuals close to the case, including Jim Cavanaugh, the ATF’s lead investigator on the D.C. Sniper Task Force and Sari Horwitz, a Washington Post reporter who covered the attacks and co-authored the book, “Sniper: Inside the Hunt for the Killers Who Terrorized the Nation.” Other interviews include a shooting victim, eye-witnesses to the crimes, criminal profilers, and Malvo’s social worker, who claims that the boy’s troubled childhood made him turn to a dangerous man like Muhammad.