The National Highway Traffic Safety Administration said Friday it will investigate a 12th Tesla crash that may be tied to the vehicle’s Autopilot driver assistance system.

Specifically, the U.S. auto safety agency will investigate the Dec. 7 crash of a 2018 Tesla Model 3 on Interstate 95 in Norwalk, Connecticut. In the incident, a Tesla Model 3 rear-ended a parked police car.

Autopilot has been engaged in at least three fatal U.S. Tesla crashes since 2016. The agency’s special crash investigation team has inspected 12 crashes involving Tesla vehicles where it was believed Autopilot was engaged at the time of the incident.

NHTSA has concluded that the Autopilot was a factor in a 2016 fatal crash in Florida.