PORTLAND, Ore. (AP) — Washington County District Attorney Kevin Barton has asked the Oregon Department of Justice to review the deadly shooting of a man by Tigard police.

In a letter to Michael Slauson, chief counsel for the criminal division of the Justice Department, Barton said he believes an “independent evaluation” of the investigation of the fatal shooting of Jacob Macduff is necessary “given the concerns I have developed regarding the incident.”

Barton declined to comment on his request or about the concerns he mentioned, The Oregonian/OregonLive reported.

Macduff, 26, was in the throes of a mental health crisis that had escalated before his death on Jan. 6, his friend Theresa Chapin said at the time.

Macduff had struggled with an undiagnosed mental health problem, Chapin said. Macduff’s mother told The Oregonian/OregonLive it might have been bipolar disorder.

His erratic behavior prompted Chapin and other friends to call 911 five times in the week before police shot and killed him. Tigard police have said he was shot as officers tried to arrest him on domestic violence allegations.

Police said officers “confronted” Macduff in his vehicle, which was parked under the apartment complex where he lived. Macduff had a knife, police said, and refused to surrender. Officer Gabriel Maldonado shot him during a struggle, police said in a statement.