The decision stems from a review of the province's bail system prompted by the fatal shooting of RCMP Const. David Wynn outside an Edmonton-area casino in January 2015.
The shooter, Shawn Rehn, was a career criminal who was out on bail at the time of the shooting.
Despite having more that 30 outstanding charges, Rehn had been released without his criminal history being presented by the police officer who conducted the bail hearing.
Wynn's death raised questions around whether Crown prosecutors with more courtroom experience should attend all bail hearings.
Const. David Wynn
Const. David Wynn, 42, was fatally shot on duty in 2015, by a man who had been released on bail despite a history of criminal and violent behaviour. (RCMP)
Alberta Justice Minister Kathleen Ganley sought a ruling from Court of Queen's Bench Chief Justice Neil Wittmann on the legality of police officers standing in on bail hearings.
Wittmann found the requisite authority does not exist. 
"As a result, the declaration will be the opposite to the one the Attorney General is seeking and the practice must cease," he wrote in his decision.

Defence lawyers disagree

Defence lawyers organizations in both Edmonton and Calgary had argued Alberta's current system, which allows police to act as agents of the Crown, was legal and should continue.
"I'm not surprised," said Ian Savage, president of the Calgary Defence Lawyers Association, of Wittmann's decision. "It was certainly a grey area in the law ... this now provides certainty in Alberta."
A pilot project has been running in Edmonton since October and Savage says early statistics from that show the number of bail hearings ending up in a courtroom have been reduced and more people are getting released.
Savage is concerned about the reduced hours under the new system — Alberta is going from a 24-hour bail system to operating from 8 a.m. to midnight.

'Experienced eyes' advantage

It's an advantage to have the "experienced eyes" of a prosecutor, Savage said, but he worries about an accused's access to a defence lawyer to go up against that experience.
Legal Aid Alberta had been participating in the project, funding a duty counsel lawyer to be available between 8 a.m. and 4 p.m., "to act as a counter balance to real prosecutors," said Savage.
But that temporary funding stopped in December.
"We're calling on the minister to implant full legal aid duty counsel funding for in-custody Justice of the Peace bail hearings for the full hours of operation of the hearing office," said Savage.

Decision not effective until August

Savage sits on a committee that is involved in expanding process throughout Alberta: Calgary is next and then rural areas will see the change.
Wittmann ruled his decision is not effective until August to give the justice ministry time to implement the changes.
It's unknown how many new prosecutors will be needed. For Edmonton's pilot project, six prosecutors plus several support staff were hired.
A spokesman for justice minister's office said planning, including staffing details, are currently underway, but the success of the pilot project has well-positioned the department to expand it province-wide by August. He said they are confident prosecutors will be in place by then.