A 20-year-old Dorchester man was arrested by Boston police today on murder charges stemming from the shooting death of Jason Withers inside a Roxbury convenience store.

Withers was inside the store at 655 Warren St. when he was shot around 4:30 a.m. on March 31. No motive has been disclosed for the killing of Withers, who was 25 years old.

But his alleged killer, Ramon Dingle-Smith, is to be arraigned today in Roxbury Municipal Court on a charge of a murder, according to Suffolk District Attorney Daniel F. Conley’s office.