Travis Vader has been found not guilty of uttering a threat to a police officer while in custody at the Edmonton Remand Centre.
The officer had alleged that Vader said he would "find him and kill him" once he was free.
However, a provincial court judge ruled Wednesday that it had not been proven beyond a reasonable doubt that Vader made the threat.
Vader said that police were mad at him for filing a lawsuit against them.
Vader had been facing first-degree murder charges in the slaying of two seniors who vanished almost four years ago, but those charges were stayed just a few weeks before the case was set to go to trial.
Lyle McCann and his wife, Marie, both in their 70s, were last seen alive as they fuelled up their motorhome in St. Albert, a bedroom community northwest of Edmonton, in July 2010.
Police discovered the charred remains of their motorhome but their bodies have never been found.
Vader has been in custody since July 2010 and is scheduled to have a trial this fall on various unrelated charges including drug trafficking and weapons offences.
He has filed two lawsuits, one claiming RCMP and justice officials kept him in custody on trumped-up charges until he was arrested in 2012 and charged in the deaths of the McCanns.
The other lawsuit alleges malicious prosecution and that Mounties botched the murder case from the beginning.
None of the allegations in the lawsuits has been proven in court.