Twenty-nine of the 30 registered sex offenders were in substantial compliance with the terms of their probation for sex offenses, Marin County Probation Department Supervisor Matt Perry said.
There is a pending investigation regarding a possible technical violation by one of the registered sex offenders, Perry said.
The probation compliance checks were made in Novato, San Rafael, San Anselmo, Kentfield and Marin City.
Four teams comprised of Marin County sheriff's deputies, Novato and San Rafael police and the county probation department conducted the checks.
Perry said the cooperation of law enforcement enables the probation department to "provide a consistently high level of supervision with this offender population."
He said, "These type of operations send a message to the offenders and community that we are working together to monitor this population of offenders within our community."