BOSTON (AP) — A third Boston police officer pleaded guilty Thursday to drug trafficking charges for protecting truckloads of cocaine during an FBI sting operation.

Roberto Pulido, 42, entered the plea following two days of damaging testimony at his federal trial.

Authorities said Pulido was the ringleader of a group of three officers who received thousands of dollars from men they believed were drug dealers but were actually undercover FBI agents. The officers escorted two truckloads of cocaine into Boston in 2006. They were arrested in July 2006 in Miami, where they went to collect $35,000 for protecting a drug shipment a month earlier.