A federal judge has ruled that Decarlos Brown Jr, the man accused of fatally stabbing a Ukrainian refugee on a Charlotte commuter train, is incompetent to stand trial at this time.

Brown, 35, is charged with killing 23-year-old Iryna Zarutska on a Charlotte light rail train in August. The US attorney's office for the western district of North Carolina announced the competency ruling on Tuesday.

Zarutska was a Ukrainian refugee who was killed in what authorities described as a violent attack captured on surveillance camera video. The footage of the incident was later released and drew national attention to the case.

Under the court's ruling, Brown will remain in custody while receiving treatment for the remainder of the case proceedings. The competency determination means the federal case cannot proceed to trial until Brown's mental state is deemed sufficient for him to understand the charges against him and assist in his defense.

The incident occurred on Charlotte's light rail system, which serves the metropolitan area with public transportation. Federal authorities took jurisdiction over the case, which involves charges related to Zarutska's death on the transit system.