The Indiana State Police seized a half tonne of marijuana worth $8 million after an alert patrol dog picked up the drug’s scent during a traffic stop.

The incident occurred on Tuesday afternoon when a trooper searched a van after stopping it for a moving violation outside Lowell, in north-west Indiana.

“During that search, troopers discovered 38 large boxes and six black garbage bags.

“The boxes are wrapped in black plastic wrap. Inside the boxes contained a total of 1,264 individually sealed bags, each weighing approximately 1.5 lbs (about 680g, and contained a green plant material. A field test of the content revealed it to be marijuana,” said the police.

The driver, 31-year-old Christopher Colburn, was arrested at the scene.

A photo of the seizure showed a white van filled with black garbage bags.

Mr Colburn has been preliminarily charged with dealing on marijuana-level five felony and possession of marijuana with prior conviction-level six felony.