Sheldon John Davis, 39, of Griffin, is facing eight charges of supplying and trafficking dangerous drugs, including methylamphetamine, resulting from evidence gathered after police pulled over his vehicle on April 13, 2009.

Constable Michael Carr and Senior Constable Brent Schulz were attached to the Moreton District Tactical Crime Squad and patrolling outside Dakabin, north of Brisbane, in an unmarked police car that day.

After spotting a black Holden Senator sedan, the officers used section 60 of the Police Powers and Responsibilities Act to pull the vehicle over.

Section 60 allows police to pull over vehicles without holding any suspicion but with the “proscribed purpose” of checking for traffic law offences such as unlicensed drivers or unroadworthy vehicles.

The officers said when they asked Davis to exit the vehicle, they spotted a bag on the driver’s seat that allegedly contained more than 20 grams of pure methylamphetamine.

Officers then used section 31 of the same act to search the car without a warrant on the basis they “reasonably” suspected it contained dangerous drugs.

Further drugs were allegedly found on Davis and a mobile phone in the car allegedly contained evidence of drug deals.

Davis’s barrister Paul Rutledge submitted that the interception of the car was “unlawful” because the officers’ real purpose in pulling over his client was not to enforce transport laws.

Rutledge argued that police used section 60 to avoid the legislative safeguard in section 31, namely that they would have to prove they had a reasonable suspicion that an unlawful dangerous drug might have been in Davis’s car without looking inside it.

The Crown’s legal team accepted that if pulling over Davis was illegal, then his detention, search and subsequent police interviews “were tainted by the illegality”.

Justice Peter Davis determined that Sen Const Schulz made the decision to pull over Davis for a licence check and Const Carr made the decision to search the vehicle.

Sen Const Schulz testified that he and Const Carr had gone out on patrol in an area near to houses “connected with drug dealers” intending to target suspected drug offenders.

In a judgment delivered on Monday, Justice Davis stated that he did not accept Sen Const Schulz’s assertions that Davis was initially pulled over to check for traffic law compliance but still found him to be an “an honest witness who was motivated to tell the truth”.

“(Sen Const Schulz’s) miscategorisation of his actions as traffic enforcement was no doubt a reflection of what he had been instructed by more senior police,” Justice Davis said.

Justice Davis ruled that evidence resulting from pulling over Davis’s vehicle be excluded as it was more in the “public interest to denounce the conduct of police in deliberately misusing powers” than to support a potential prosecution for alleged serious drug offences.