Retired Phoenix police officer Paul Penzone announced Tuesday that he'll challenge Maricopa County Sheriff Joe Arpaio in November.
Penzone is running as a Democrat and joins Scottsdale police Lt. Mike Stauffer in challenging the five-term Republican sheriff.
Stauffer is running as an Independent.
Penzone worked for the Phoenix Police Department for 21 years and was director of the Silent Witness program.
His campaign announcement accused Arpaio's office of financial mismanagement and leveled criticism at the office for either inadequately investigating or not investigating at all hundreds of sex-crimes cases.
Arpaio has refused calls from critics to resign because of the botched the sex-crimes investigations and allegations that his office racially profiles Latinos.