A 29-year-old convicted felon who gunned down a man trying to protect his mother during a robbery, will spend the rest of his life behind bars.

DeKalb County Superior Court Judge Gail C. Flake sentenced Demarcus McClarin of Lithonia on July 14 to two consecutive life sentences plus five years for the 2008 murder of 36-year-old Mac Mayer. McClarin shot and killed Mayer on April 9, 2008, while McClarin was robbing his mother, Ad Mayer-Lillard, at gunpoint in the parking lot of Belvedere Theater on Columbia Drive in Decatur which she owned.

Mayer died from a single shot in the back.

McClarin had previously served at least three years in prison for illegally receiving and transporting firearms before he was released on Jan. 18, 2008.

A DeKalb jury convicted McClarin on June 26 on seven felony charges including malice murder, felony murder, armed robbery, two counts of aggravated assault, possession of a firearm during the commission of a crime and possession of a firearm by a convicted felon.

Assistant district attorneys Courtney L. Johnson and Zina B. Gumbs prosecuted the case.