Edmonton's former police chief says a man charged in a truck attack in the city last year had an encrypted device police couldn't crack.

Rod Knecht was at an international counter-terrorism gathering in Melbourne and told Australian newspaper the Sydney Morning Herald that encryption laws should be changed to allow police to hold terrorists to account.

Knecht referred to an attack in September 2017 in which an Edmonton police officer was hit with a car and stabbed with a knife outside a football game.

Later that night, a speeding cube van hit and injured four pedestrians as it raced through the city's downtown with police in pursuit.

Abdulahi Hasan Sharif is scheduled to go to trial next year on attempted murder and dangerous driving charges.

Police said at the time that an Islamic State flag was found in the car used in the attack, but no terrorism charges have been laid against Sharif.

Knecht told the newspaper Sharif had a device police couldn't get into.

"If we could have accessed that device it would have pushed the investigation forward. It would have demonstrated who else was involved, because in situations where it looks like there was only one person involved, oftentimes there was someone else who helped along the journey," Knecht is quoted as saying.

"A lot of times, these people aren't held to account for killing people."

The newspaper did not specify what the device was.

Const. Mike Chernyk was injured when a driver crashed through a barrier, got out of his vehicle, pulled out a large knife and began stabbing him the evening of Sept. 30, 2017. The driver got away.

Police set up checkpoints and began stopping cars. That led to a second encounter with the suspect who was driving a U-haul cube van.

Knecht said when the U-haul pulled over for the checkpoint, the driver was confronted after he produced identification linking him to the registered owner of the car involved in the attack on Chernyk.

The van then sped off toward downtown with multiple police cars in pursuit. It veered into alleys and cross-streets through the downtown amid late-night bar and nightclub goers. Knecht said the truck deliberately hit four pedestrians.

"He just started running down people," Knecht told the newspaper.

The following day, Prime Minister Justin Trudeau called it a "terrorist attack."

Sharif has been found fit to stand trial on 12 charges. A date has been set for October 2019. He has not yet entered a plea.

Incoming Edmonton police chief Dale McFee was asked about Knecht's comments and declined to comment saying the case is before the courts.