Baltimore Police Commissioner Kevin Davis has asked the FBI to take over the investigation into the death of Detective Sean Suiter.

Davis made the request in a formal letter submitted Friday to Federal Bureau of Investigations Director Christopher Wray. An FBI spokesman said the agency is aware of the request, but otherwise declined to comment.

Davis announced his decision at a news conference Friday, saying that a connection between Suiter’s case and a sweeping, ongoing police corruption case — in which Suiter was scheduled to testify as a federal witness the day after he was shot — had diminished his faith that his own detectives could handle the death investigation while in the dark about the corruption investigation.

He also acknowledged that handing over the investigation could ease public concerns about whether it would be objective.

Suiter, a homicide detective, was fatally shot in the head Nov. 15 amid what police have described repeatedly in recent weeks as a violent struggle with an unknown suspect on a troubled block in West Baltimore, the Baltimore Sun reports.

No suspects have been identified in the case.