Twenty-one people have been arrested for soliciting and/or brokering deals for various sex acts with children, Surprise police said Wednesday.

The Surprise Police Department Criminal Investigations Division recently partnered with the Scottsdale, Glendale, Goodyear and Peoria police departments for Operation “Back to Skool.”  

Homeland Security Investigations, the U.S. Marshals Service and the Maricopa County Attorney’s Office also were part of the operation.

The Valleywide undercover operation targeting the demand for child sex crimes and human trafficking resulted in 21 arrests by Surprise police, department officials said.

Undercover detectives placed ads on websites commonly sought out by suspects seeking illegal sex acts, according to authorities.

“Operations of this type are a part of the Surprise Police Department’s continuous effort to reduce the demand that fuels child sex trafficking and exploitation of children in our community,” a Surprise Police Department release stated.