Last Updated Jan 31st, 2020 at 3:13 pm

The City of Phoenix Police Department announced Thursday that 27 Phoenix men have been arrested in a joint-agency investigation of child sex crimes.

Four separate Phoenix police departments partnered with Homeland Security and the Arizona Attorney General's Office in an undercover sting investigation called "Operation Silent Predator."

Undercover officers posted ads on websites and apps known to be used by sex predators to arrange sexual encounters with individuals whom suspects thought were children ages 14 or younger.

During a press conference Thursday, Phoenix Police Chief Jeri Williams pleaded with parents to monitor their children's online activity more closely.

"If we choose not to monitor, bad things can happen," she said. "There are people in our social media world who will hurt us or hurt our children if we don't do the responsible thing."

The men arrested are listed below: