FRAMINGHAM, Mass. — A Massachusetts teenager has pleaded guilty to making hoax threats that prompted police responses in several states.

State police say the 17-year-old Andover boy led an online ring of hackers who made so-called "swatting" calls to Massachusetts, Rhode Island, New York, and Florida. Swatting is the term used for provoking a police response with fake threats.

Federal, state and local law enforcement began investigating in April. Police executing a search warrant found an Anonabox router — a device that allows an anonymous internet connection — in his bedroom. Police also found evidence of online messaging between several people talking about bomb threats they had made.

The boy pleaded guilty last month to conspiracy and bomb threat charges. He was placed in state Department of Youth Services' custody until his 21st birthday.