Operation Visitor led to the detection of 58 offenses committed by YOI visitors, leading to 25 arrests. Operation Visitor provided empirical support for the intuitive belief that a significant number of prison visitors themselves have offending histories. Often the detection of visitors' minor offenses, such as a vehicle traffic violation, uncovered more serious offenses. Visitors who drove to the YOI were found committing driving/vehicle-related offenses significantly more often than the general population. The evaluation recommends continuing Operation Visitor. Visitors anticipated being searched and having to produce necessary documentation as a condition of entry to the prison. Although vehicle checks were unanticipated, all visitor vehicles were checked. All checks were conducted by police officers/staff. All further background checks of offending visitors were conducted by police officers, and confidentiality was maintained throughout the evaluation research. The evaluation obtained data on visitors and their vehicles, total offenses by visitor, types of offenses visitors committed, profiles of visitor offenders, and visitor offending histories and current offending. 5 tables and 11 references