The department said Drequan Lamont Robinson, 18, was arrested on charges of capital murder and aggravated robbery.
According to police, Robinson is suspected of being one of two armed men who held up a Valero gas station at 601 W. Broadway St. about 11:38 p.m. Friday. Shawn Mckeough Jr., a 23-year-old U.S. Air Force specialist, tried to stop the holdup. One of the robbers fatally shot Mckeough.
Anyone with information on the killing is asked to call North Little Rock police at (501) 771-7167 or (501) 680-8439.
The department is offering a $10,000 reward for information leading to an arrest and conviction.