The head of the Chicago Police Department announced his resignation Wednesday, hours after Chicago Mayor Lori Lightfoot lost her bid for reelection.

Chicago Police Superintendent David Brown is resigning effective March 16, Lightfoot said in a statement. He turns 63 in October of this year – the mandatory retirement age for Chicago police officers.

Paul Vallas, 69, the former head of Chicago Public Schools, and Brandon Johnson, 46, on the Cook County Board of Commissioners, came out as the top two vote-getters. Both have said they would replace Brown if elected, USA Today reports.

First Deputy Eric Carter will be appointed as interim superintendent until the new mayor is sworn into office, Lightfoot said. She called on the city's newly formed civilian police oversight body – the Community Commission for Public Safety and Accountability – to immediately begin the search for a new superintendent.

In a statement, Brown said he accepted a job as Chief Operating Officer of Loncar Lyon Jenkins, a personal injury law firm with seven offices in Texas. He said he's stepping down "so the incoming mayor can begin the process as soon as possible to hire the next Superintendent."