The Justice Department charged the man accused of fatally stabbing a Ukrainian refugee on a Charlotte light rail train with a federal crime on Tuesday, the latest escalation in a case that has sparked national scrutiny over what led to the fatal attack.

Decarlos Brown Jr., 34, was charged Tuesday in U.S. District Court in Charlotte with committing an act causing death on a mass transportation system. The charge stems from the Aug. 22 killing of Iryna Zarutska, a 23-year-old woman who boarded the Lynx Blue Line moments before she was allegedly attacked from behind by Brown, and could carry up to life in prison or the death penalty if convicted.