It was a Crime Stoppers tip that gave agents the break they needed in the case, FBI spokesman Kevin Rowson said.
That tip led authorities to a residence in the 1200 block of Thorncliff Court in Lawrenceville, where Watson was taken into custody.
According to police, Watson shot Miles several times following an argument outside of the clothing store in the 1700 block of Howell Mill Road. Witnesses told police he sped from the scene in a black sedan.
Miles, 48, of Atlanta, was taken to Grady Memorial Hospital, where he later died from his injuries. In music circles, Miles went by the name Ensayne Wayne. He worked with Three 6 Mafia, 8Ball and MJG and Lil Wayne. He produced the beat for "Shawty," the 2008 hit from rappers Plies and T-Pain.
In an Instagram post shortly after the deadly shooting, Drumma Boy wrote: “I lost the first person I ever looked up (to) in life ... the first person I ever wanted to be like ... my big blood-brother.”