Fired Rochester police chief La'Ron Singletary is running for Congress.
Singletary has notified the Federal Election Commission of his plans to run as a Republican for the 25th District seat now held by Democrat Joe Morelle.
A campaign website is already online.
A formal announcement is expected this morning.
Mayor Warren fired Singletary last year after the public disclosure about the death of Daniel Prude, and allegations of a coverup.
Singletary later sued the mayor for defamation.