Eirik Jensen, 60, who was in charge of fighting organised crime, is accused of aggravated corruption and having being involved with an infamous drug trafficker, Gjermund Cappelen, also known as the "hashish baron", for several years.
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Jensen denies the accusations against him in the extremely rare case of alleged official graft, which has made headlines in Norway for several months.
International rankings routinely list the country as one of the world's least corrupt nations.
Jensen allegedly received 2.44 million kroner (over 262,000 euros, $293,000) in bribes, in exchange for helping Cappelen smuggle 13,9 tonnes of hashish into Norway between 2004 and 2013, according to prosecutor Guro Glaerum Kleppe.
She mentioned multiple message exchanges between the men, adding they included code language on police activity. The two men are now sworn enemies.
Kleppe said Cappelen, 50, who was arrested for drug trafficking, provided information about Jensen's alleged role in drugs smuggling to investigators, hoping to have his punishment reduced.
On Friday, prosecutors demanded that Cappelen be sentenced to 18 years in prison.
The two men's lawyers will make their respective pleadings early next week.
In neighbouring Finland, a court sentenced a former chief detective of the Helsinki police drug squad to ten years in prison last year for taking part in a drug smuggling ring.