Chicago (CBS) — A national operation to deter johns and interrupt the online havens of sex trafficking netted almost 400 arrests nationwide, including more than 50 in Illinois alone.

More than 20 police agencies in 14 states participated in the 17th National Johns Suppression Initiative (NJSI) Jan. 13 through Feb. 3.

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The Cook County Sheriff’s Office arrested 38 sex buyers, Sheriff Thomas J. Dart said. The arrests included joint operations with the Lansing, Matteson and Orland Hills police departments.

In Lake County, 14 johns were arrested, and three were arrested by the Rockford Police Department.

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Law enforcement agencies posted decoy ads on more than a dozen trafficking-related websites, which led artificial intelligence bots to deter johns and, in many cases, to police officers who made arrests.

The AI bot interacts with bots and eventually sends a deterrence message warning of the legal and social dangers of buying sex. Agencies that used the bot engaged 1,477 potentially sex buyers with nearly 8,500 messages sent. In Cook County, the bot engaged 159 contacts.

The Cook County Sheriff’s Office arrested one individual, who is a high-frequency sex buyer, and sent more than 350 text messages and placed nine phone calls to bot phone numbers.

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Since the NJSI began in 2011, more than 9,000 johns have been arrested nationwide.