Port Huron police say they joined federal, state and local authorities in a two-county sweep to verify the registration of 750 sex offenders.
Police said Monday that the three-day sweep led to the discovery of 40 violations and 11 arrests.
Participants in the sweep included the U.S. Marshal Service, Michigan State Police and various law agencies in St. Clair and Lapeer counties.
The Michigan Sex Offenders Registration Act requires listed people to regularly report to police to verify their addresses. Registrants also have three business days to report any changes in name, address, employment, college enrollment, Internet identifiers and vehicle.
Failure to do so is a felony with a penalty of up to four years in prison.