Minneapolis Police Chief Brian O’Hara resigned Tuesday after Mayor Jacob Frey determined he interfered with an internal investigation into allegations of inappropriate relationships with city employees.

While the original probe found the allegations unsubstantiated, investigators discovered O’Hara deleted a contact from his city phone and improperly discussed the investigation with another employee.

Mayor Frey called the interference a “breach of trust” and said he planned to fire O’Hara, who instead chose to resign. Assistant Chief Katie Blackwell will serve as interim chief.