LANSING, Mich. (AP) — State police say 37 of Michigan’s 203 desktop alcohol-breath devices have been returned to service.

The head of the state police, Col. Joe Gasper, updated lawmakers on an investigation that could raise questions about some drunken driving cases.

State police are investigating whether any crimes were committed by contractors who must certify that the machines are properly calibrated.

Gasper identified eight police agencies with “discrepancies” in 52 breath tests linked to the DataMaster DMT machines, including some that go back more than a year.