WASHINGTON (AP) — A former Republican filed paperwork Wednesday to run for District of Columbia mayor as an independent, setting the stage for a competitive race in the midst of a scandal involving current Mayor Vincent Gray’s 2010 campaign.

Council member David Catania could pose a challenge to the Democratic nominee in this year’s general election, even though the district is heavily Democratic. Catania, who is gay, has a progressive record and left the Republican Party in 2004. He first won a citywide at-large council seat in 1997 and has been re-elected four times.