MADISON, Wis. (AP) -- Democratic Milwaukee Mayor Tom Barrett said in Thursday's debate with Gov. Scott Walker that during his years in public service, no one on his staff has ever been charged with a crime.

But in November 2010, Barrett's office receptionist Joseph N. Cantu pleaded guilty to two counts of battery and one count of disorderly conduct related to a fight with his ex-girlfriend.

Cantu was placed on unpaid leave after he was charged. He earned about $15,000 a year in the job and was 23-years-old at the time.

Walker's campaign spokeswoman Ciara Matthews is accusing Barrett of lying during the debate and says he owes people an apology.

Barrett's spokesman Phil Walzak says Barrett was clearly talking about senior political aides doing work to further their own political careers.