MADISON, Wis. — Police have cited another 22 protesters as their crackdown on anti-Republican sing-alongs in the Wisconsin Capitol goes on.

Protesters have been singing songs against Republican Gov. Scott Walker in the rotunda almost every noon hour for more than two years. Police began citing them on July 24 for lacking a permit, handcuffing them and leading them away to their basement headquarters.

They've issued more than 160 citations. On Tuesday they cited another 22 protesters for not having a permit. They also cited one of the 22 for disorderly conduct.

State Sen. Jon Erpenbach, a Middleton Democrat, sent a letter to Capitol Police Chief David Erwin asking why officers handcuff and detain protesters for a municipal violation. A state Department of Administration spokeswoman says Capitol Police are following standard police protocol.