Court of Queen's Bench Justice Brian Burrows acquitted the teen after tossing out evidence gathered by RCMP in a so-called "Mr. Big" sting.
The decision angered the victims' families, prompting one man to stand and scream at the teen, "Go to hell." Other family members also stood and began swearing at the teen.
Security guards rushed into the courtroom and escorted the teen from the prisoner's box back to cells, and the judge quietly left the court.
The RCMP's “K” Division released a statement following the verdict saying it respects the court’s decision.
“Although the evidence presented at trial did not result in a conviction, the RCMP is satisfied that we conducted a thorough investigation in this case,” the statement reads. “The RCMP will not be seeking other suspects in this matter.”
The accused teen, who turned 18 today, was charged with two counts of second-degree murder in the June 2009 deaths of Susan Trudel, 50, and Barry Boenke, 68, on a rural property near Ardrossan, Alta.
His identity cannot be revealed under provisions of the Youth Justice Act.
In his decision, Burrows blasted the Mr. Big operation saying the RCMP may have abused its power, violated the teen's rights and coerced a confession.
"Aspects of the circumstances of the Mr. Big operation in this case give rise to abuse of power concerns," he said.
Admitting the evidence could "bring the administration of justice into disrepute," he added.
The accused and another teen had run away from a nearby treatment facility run by Bosco Homes. They were caught joy-riding in Boenke's truck just hours after the couple were bludgeoned and shot to death.
The teens were arrested and charged, but the charges were eventually stayed when a judge refused to admit a police interview as evidence. No charges were ever returned against the second teen, who testified as a Crown witness against the accused.
During the Mr. Big operation, RCMP officers posed as gangsters and tried to gain the teen's trust to get a confession.
Statements made by the teen during the operation were the subject of an ongoing hearing within his trial to determine whether they could be admitted as evidence.
Burrows said the teen's statements to Mr. Big may have been coerced.
"In my assessment, the circumstances give rise to a very real and very strong prospect that his confessions to Mr. Big are unreliable," he said.
Burrows said there was nothing in the teen's statement to Mr. Big that he could not have learned at a preliminary hearing that took place prior to the original charges being dropped.
Burrows also found that the teen's rights under the Charter of Rights and Freedoms may have been violated during the operation.
Burrows did find the teen guilty of stealing Boenke's truck, sentencing him to probation for one year.