Christoper Heath, 37, who was part of an anti-drugs squad in Yuba County in the state was arrested with two others after police were informed the men were delivering 122 marijuana packages to West Mannheim in Pennsylvania.

But investigators were shocked when they discovered Mr Heath was a fellow police officer. They found his badge and firearm in the car he used to deliver the drugs from California.

Mr Heath and the two other men were charged with the possession and delivery of illegal drugs as well as criminal conspiracy – each was released on $1m bail.

As an anti-narcotics officer, Mr Heath led 62 criminal investigations – many marijuana-related – reports the Appeal-Democrat newspaper.

Last year he testified in a federal case against a Texas man accused of involvement in a family marijuana- trafficking ring.

Yuba County authorities are attempting to establish whether any of his cases were tainted by his alleged drug activities.