A former New York state prison investigator faces criminal charges after authorities say he falsified evidence handling records.

New York State Inspector General Letizia Tagliafierro on Tuesday said former investigator Todd Johnson has been arrested. Her office says Johnson falsified evidence records in one instance and "likely falsified or caused to be falsified evidence" in 52 separate cases from northern New York.

The cases were narcotics investigations involving prisoners and prison visitors.

Her office reports the 55-year-old former investigator is charged with second-degree forgery and first-degree offering a false instrument for filing, both felonies. He also faces misdemeanor charges.

The office says Johnson falsely reported on a daily activity log and "improperly" stored evidence at his home.

Johnson's attorney Derrick Hogan says his client pleaded not guilty on Tuesday.