A third challenger to Sheriff Joe Arpaio has entered the race for Maricopa County Sheriff. 

John Rowan, standing with campaign staff and volunteers, carries his box of nominating signatures in the Maricopa County Elections office. (Photo by Nick Blumberg - KJZZ)

John Rowan worked for the New York City Police Department for 20 years. He’s lived in Maricopa County for six. And Tuesday afternoon, he filed nearly 5,000 nominating signatures to run for Maricopa County Sheriff.

Rowan’s been described as a “conservative Democrat,” but he said that’s not accurate. “I would describe myself as a progressive, reform Democrat," Rowan said, "and I’m looking to reform MCSO.”

Among those reforms, Rowan wants to start a civilian complaint review board to look into allegations against deputies. He also wants to audit MCSO’s finances, and to guarantee that "a case will never go uninvestigated, and God forbid, if it was ever to happen, that detective would be fired by the end of the day.”

Rowan admits he hasn’t raised much money thus far, but describes his campaign as grass roots. He’ll face former Phoenix policeman Paul Penzone in the Democratic primary on August 28.