St. Louis County Assessor Jake Zimmerman says he is running for attorney general in 2016.
Zimmerman announced his candidacy Tuesday, setting up a potential Democratic primary against state Sen. Scott Sifton of St. Louis County, who already has entered the race.
The Missouri attorney general's office will be open next year because Democratic incumbent Chris Koster is running for governor.
Zimmerman says he served as an assistant attorney general in 2002 and 2003. He later spent several years in the Missouri House representing a St. Louis County district. Zimmerman was elected as assessor in 2011 and re-elected last fall.
State Sen. Kurt Schaefer, of Columbia, is the only Republican in the attorney general's race.