CINCINNATI (AP) — The mayor of Cincinnati has tearfully apologized to city police after his office unwittingly approved a proclamation honoring a man suspected of killing an officer in an ambush.

Mayor John Cranley delivered his apology Thursday at the police union hall, saying the proclamation was stamped by a new staffer.

The proclamation designated June 1, 2017, as “Tre Day” in honor of Trepierre Hummons. Investigators say Hummons was hoping for “suicide by cop” when he killed Officer Sonny Kim in June 2015 before being gunned down by another officer.

The mayor said a request for the proclamation, submitted by Hummons’ father, did not mention Hummons’ full name. The request said a proclamation would honor his commitment to fighting mental illness.

The proclamation has been retracted.