EDMONTON — A lawyer for a suspect in a case involving two Alberta seniors who vanished four years ago is planning to challenge the reactivation of old murder charges.

Travis Vader, 42, was re-arrested last week on two counts of first-degree murder in the deaths of Lyle and Marie McCann. The couple, both in their 70s, were last seen fuelling up their motorhome in their hometown of St. Albert, a bedroom community north of Edmonton, in July 2010.

The charges were stayed in March, a few weeks before Vader was to have a jury trial. He was released from custody in October after being found not guilty of unrelated drug and weapons offences.

Vader was to be freed again Tuesday, after a judge granted him $25,000 bail on the condition that he remain under house arrest.

Defence lawyer Brian Beresh told reporters after the bail hearing that he will be mounting a court challenge. He said it's rare for the Crown to reactivate murder charges and officials have provided no explanation.

"There has to be some exceptional circumstance," Beresh said. "I have no new information about any new evidence whatsoever."

Crown prosecutor Ashley Finlayson said outside court that he's not sure if the reactivation can be challenged.

He said that the Crown's office originally stayed the murder charges because there was a "disclosure issue" and the case needed to be reviewed. The Crown had a one-year time limit to renew the charges.

"A decision had to be made prior to the expiration of that stay period," said Finlayson.

"The assessment was that it was in the public interest to proceed with the matter and there was a reasonable likelihood of conviction and that would have been based on the material that was available."

He wouldn't say if there is new evidence in the case.

"There's additional material because time has passed. Beyond that, I can't comment."

The bodies of the McCanns have never been found but RCMP say in court documents that they believe the pair were killed.

Their burned out motorhome was discovered a few days after they were last seen in St. Albert. They had been on their way to British Columbia for a family camping trip.

Mounties soon named Vader a person of interest and later a suspect in the case and he was held on unrelated charges until he was charged with the killings in 2012.

Earlier this year, Vader filed lawsuits against prosecutors and the RCMP claiming malicious prosecution. He alleges he was kept in custody on trumped-up charges until he could be charged with murdering the McCanns, as well as mistreatment by staff in the Edmonton Remand Centre.

When Vader walked out of the remand centre in March, he told reporters that he knew nothing about the McCanns and had been the subject of a witch hunt by the justice system.

Beresh said his client enjoyed his 10 weeks of freedom and was surprised when police arrested him again last week. "He was leading a normal life, taking courses, doing various things in the community, assimilating back into society."

Vader is to appear in court again Jan. 23. Finlayson said the case will continue where it left off before the stay of charges and a new trial date will be set.