Criminal lawyer Brian Beresh is prepared to go on the attack this week in an Edmonton courtroom on behalf of his client, Travis Vader, who has been charged with two counts of first-degree murder in the case of a missing Alberta couple.

Lyle, 78, and Marie McCann, 77, of St. Albert disappeared in July 2010 and their bodies have never been found.

Beresh will grill the RCMP and the chief Crown prosecutor, Michelle Doyle, about the way they handled the case.

He is expected to ask for a judicial stay of proceedings, citing an abuse of process by the Crown.

A mountain of evidence has been gathered by the Mounties. More than 600 investigators have worked on the file. There are tens of thousands of pages of disclosure.​

But the Crown now admits the reason it asked for a stay of proceedings on the murder charges in March 2014 on the eve of the trial was because Mounties discovered a lot of the evidence wasn't passed along to the Crown or the defence.

Crown looks to blame RCMP

According to submissions filed last week by both sides, it appears the Crown is prepared to place all the blame on the RCMP.

The brief states: "Ms. Doyle elected to enter a stay of proceedings as opposed to making an application for adjournment because she had effectively lost confidence in the RCMP getting full disclosure to her in a timely manner."

The Crown's brief uses the description "disclosure fiasco," and admits the disclosure issues "are egregious and cannot be condoned."

The document also reveals the sergeant in charge of the investigation "spent virtually 10 to 12 hours a day trying to put this derailed disclosure train back on the tracks."

Crown prosecutor Ashley Finlayson is now assigned to this case, replacing Doyle, who has been promoted to chief Crown prosecutor.

Finlayson writes in his brief that major changes have since been made within the RCMP to fix "the poor disclosure practices of the police."

Mounties have now moved the Major Case units from various detachments to one centralized unit in Edmonton. RCMP have also hired more support staff to assist investigators with the disclosure process.

Defence lawyer Brian Beresh has been openly critical of the Crown and RCMP.

Evidence 'shoddily gathered'

When the charges were stayed in March 2014, Beresh said the evidence was "shoddily gathered and it was a bunch of strings that were never tied together."

He added, "I'm also amazed at how poorly the information was provided to the defence."

He will argue the judge should impose a stay of proceedings to "protect the fairness of an accused's trial and/or to protect the integrity of the justice system."

Beresh claims Vader's charter rights have been clearly violated through the delays and lack of timely disclosure.

If Beresh's bid to get the charges thrown out fails, he wants the judge to stop the Crown from making any use of any evidence or materials gathered or not disclosed after the first stay of proceedings was entered in March 2014.

That would include two interviews RCMP conducted with Vader in December 2014 after the murder charges were recommenced.

Fascinating glimpse into details of case

While the actions of the Crown and the RCMP will be open for attack this week, the materials filed last week with the court provide a fascinating glimpse into some details of the police investigation never heard before.

There was an undercover surveillance operation the Crown admits "didn't result in any meaningful evidence but still should have been disclosed."

There were wiretaps, an undercover operation involving Vader and his sister, plus payments made to an agent who was a potential Crown witness.

The Crown's brief also reveals that after the March 2014 stay of proceedings, RCMP essentially conducted no further investigation into the murders other than checking tips that came in.

Mounties obtained a tracking warrant to put on Vader's vehicle in May 2014, but never used it because he was still in custody on other charges.

The final decision in the case rests with Alberta Court of Queen's Bench Justice Denny Thomas.

He will have to decide if there's been an abuse of process and if the first-degree murder trial should proceed next March.

And if it does go ahead, he must decide what evidence can be presented at trial.

The Crown insists its actions have been "laudable," and that all steps taken were done to protect the justice system and Vader's right to a fair trial.

The defence argues this is a clear case of the Crown unfairly asking for a stay and an abuse of process.

The hearing starts Monday and is scheduled to go all week.