There was a phony menacing crime boss, fake drug deals, a sham robbery — even a carefully staged murder scene, complete with sheep’s blood and a tarp-wrapped mannequin for a corpse.

More than three decades after the 1974 killing of Beverly Smith, it seemed a controversial investigative police technique known as the “Mr. Big” sting had landed Durham Regional Police their man, eliciting a murder confession from long-time suspect Alan Smith in the region’s oldest cold case.

But the elaborate, nearly year-long undercover operation crumbled inside an Oshawa courtroom Friday as an Ontario Superior Court judge ruled all of the evidence gathered during the sting inadmissible at trial.

Police had “pushed the envelope,” Justice Bruce Glass wrote in his quietly scathing ruling — their tactics had violated Smith’s Charter rights, were an abuse of process, and the sting had produced confessions so unreliable you could “drive a Mack truck” through all the holes.

“In my opinion the use of this information obtained in this manner would shock the sense of trial fairness to Canadian society,” he wrote.

The verdict comes just weeks before a Supreme Court of Canada judge is set to deliver a pivotal ruling on the “Mr. Big” technique, a highly contentious gambit that has been accepted in many previous Canadian cases but that has come under scrutiny in recent years.

In 2009, after falsely believing he had become involved in a murderous crime ring, Smith gave two widely varying confessions to undercover officers, claiming responsibility for fatally shooting 22-year-old Beverly Smith (no relation) inside her Oshawa home in 1974. Durham police slapped him with a first-degree murder charge.

It was the second time Smith had been charged in Beverly’s death. In 2008, police charged him with second-degree murder after Smith’s ex-wife Linda came forward with new information.

But her evidence was quickly proven false and the charge was dropped. Six months later, police launched the Mr. Big operation.

Glass’s dismissal of the sting evidence means Smith is all but a free man. Crown lawyer Paul Murray said Friday that it was “not a likelihood” the trial will continue, though the matter returns to court July 28 as the Crown decides how to proceed.

Released on the condition that he return to court next week, Smith walked out the front doors of the courthouse flanked by his siblings and lawyers, free for the first time in more than four years.

“I’m glad to be out and to be with my family,” he said, appearing tired.

The scene was oddly reminiscent of his first court victory in 2008, when he walked out the same doors with many of the same family members after the second-degree murder charge was dropped. At that time, he’d thanked them for their support during a “terrible ordeal.”

Defence lawyer Alison Craig said she could not comment on the outcome until after the next court date, but said outside court her client was “in a bit of shock at the moment.”

Members of Beverly Smith’s family initially attended court for the first portion of Glass’s ruling Friday, but left when he announced the evidence would not be accepted. A visibly upset family member declined to comment.

In testimony earlier this year, court heard of the elaborate police tactics used to convince Smith he was involved in a crime ring.

The operation, dubbed Project Fearless, began in early 2009 by luring Smith in with his favourite pastime, fishing. Police whisked Smith away for the weekend by telling him he had won a weekend fishing package.

Posing as another lucky contest winner, an undercover officer quickly befriended Smith, a broke loner fresh out of jail and living in his daughter’s basement.

Over the next few months, Smith and the undercover officer, who cannot be identified because of a publication ban, bonded over numerous fishing trips and became close friends.

Gradually, the undercover officer began involving Smith in fake criminal endeavours, including small drug deals, and paying him for help.

Before long, Smith was introduced to his new friend’s crime boss, the so-called Mr. Big. In July 2009, the fake criminal organization told Smith about its scheme to rob a drug dealer of $80,000.

Smith was then told the robbery went wrong. When he drove to an industrial area at Keele St. and Highway 407 to help, he found Mr. Big slathered in fake blood, standing over what Smith believed was a dead body — a weighted-down mannequin wrapped in tarps.

Smith helped him burn evidence and drop the fake body off a cliff. Soon after, Mr. Big told Smith he needed some incriminating information about him, as insurance that Smith wouldn’t go to police about the murder.

Smith then gave the first of two confessions, that he killed Beverly Smith alongside another man. The undercover operation continued for another six months, at which point Smith made a second confession, that he alone killed Beverly Smith.

The so-called Mr. Big technique — a made-in-Canada investigative tool — emerged in the early 1990s in British Columbia. Between 1997 and 2004, 180 such investigations were conducted in that province alone.

Loading... Loading... Loading... Loading... Loading... Loading...

The subterfuge involves convincing the target of an investigation that he or she is consorting with criminals and must confess to a serious crime to gain trust and entry into the criminal group.

Courts have ruled that staged situations and subterfuge are allowed during the investigations of serious crimes, and the Mr. Big tactic has been used hundreds of times and employed in some high-profile cases.

Police arrested Shawn Hennessey and Dennis Cheeseman — two men connected to the slaying of four RCMP officers in March 2005 near Mayerthorpe, Alta., — after obtaining confessions through the technique.

But critics say the gambit, which is not allowable in the U.S., is unethical and produces unreliable confessions. The now-deceased Rubin (Hurricane) Carter, who served 20 years in prison in the U.S. for a murder he did not commit, called the stings a dangerous threat to civil rights.

In one case of a Mr. Big sting gone bad, Kyle Unger was convicted of the 1990 killing of 16-year-old Brigitte Grenier, based in part on a confession produced by a Mr. Big sting and a hair found at the crime scene.

A decade later, DNA testing showed no trace of Unger on any of the exhibits and could not link him to the crime scene. The Minister of Justice quashed his conviction, ordering a new trial. The charges against him were dropped because the Crown did not have sufficient evidence.

The Supreme Court of Canada has peripherally examined issues stemming from Mr. Big investigations, but it has never scrutinized the tactic square on — until now.

In August, a Supreme Court of Canada judge will rule on a Mr. Big investigation of Newfoundland man Nelson Lloyd Hart, who was convicted of murder in the drowning deaths of his twin daughters after making incriminating statements to undercover officers.

In 2012, the Newfoundland Court of Appeal reversed Hart’s murder conviction, ruling Hart realistically had no choice but to confess to the crime in the scenario police had created. The Mr. Big operation had brought Hart the friendship and money he yearned for all his life, and the judge ruled Hart would have said anything to keep it that way.

Timothy Moore, a York University psychology professor who has researched the Mr. Big technique, said the upcoming Supreme Court ruling will be “pivotal” in determining if Canadian police should keep using Mr. Big.

“It will provide an answer, one way or another, on the acceptability or the degree of acceptability,” Moore said.

Alongside Toronto lawyer Peter Copeland and fellow York professor Regina Schuller, Moore authored “Deceit, Betrayal and the Search for Truth,” the first major legal and academic study on the Mr. Big scenario.

Calling the tactic a “fundamentally deceitful exercise,” the study says there is a real concern it may cause innocent people to confess.

In an interview, Moore called the tactic “inherently problematic.”

“Police go to a lot of trouble and expense — and spend an extraordinary amount of time and energy — contriving a situation where an innocent person might have more reason to lie about committing a murder that they did not commit than they do to tell the truth.”