A 60 year old Fort Gratiot Township man, described as a “sexual predator” by the the St. Clair Clair County Sheriff’s Office, is in custody. Mark Robert Olson was arraigned on numerous charges following an anonymous tip that revealed a history of sexual misconduct and child pornography. The alleged crimes were committed in both Fort Gratiot Township and the City of Port Huron between 2001 and 2008. Olson is charged with five counts of first degree criminal sexual conduct and three counts of possession of child sexually abusive material. He is currently being held in the St. Clair County Jail and is due back in court December 23rd. Sheriff Tim Donnellon, in a statement to WPHM, says the investigation is still ongoing and more charges are expected. Anyone who may have been a victim of Mark Robert Olson is asked to contact the St. Clair County Sheriff’s Office at 987-1728.