Police used free trips, alcohol, clothing and even tickets to a Montreal Canadiens game in an undercover operation to get a murder suspect to confess to killing his mother.

Victoria Rae Brauns-Buckley was 57 when she was found dead in 2012 in the home she shared with her son, John Buckley, in Chester Basin, N.S.

John Buckley's confession came through a "Mr. Big" sting — when undercover officers pose as criminals to draw confessions from suspects.

In January, the confession was ruled inadmissible by Nova Scotia Supreme Court Justice Josh Arnold, prompting the Crown to withdraw the first-degree murder charge against Buckley.

The court released Arnold's full decision today, revealing details about the RCMP sting, dubbed Operation Hackman, which ran from 2015 to 2016.

In the days immediately following his mother's death, Buckley was charged with second-degree murder. He was held in custody for nine months before that charge was withdrawn and he was released from jail.

At the time of the sting, Buckley was living in Montreal on welfare. He had no fixed address and was working part time in a coffee shop.

According to Arnold's decision, police posing as members of a criminal gang made contact with Buckley 77 times during the sting. Officers accumulated up to 1,000 hours of audio recordings and spent more than $300,000.

Police were eventually able to ensnare Buckley by giving him a job interview with a fictitious company. He was paid $20 per hour and started working in a warehouse. His work soon involved travelling around Quebec and to destinations as far away as the Yukon. The "company" paid all his expenses on these road trips, including nights out drinking and occasionally clothing.

He was even taken to a Montreal Canadiens game, where the company bought him a Habs jersey.

The undercover officers repeatedly stressed to Buckley that the organization was like a family and that loyalty was important. Buckley was introduced to the head of the organization, the so-called Mr. Big.

They gave him a taste of the good life, not only by paying his expenses, but also by letting him see and handle gold and large quantities of cash. They also involved him in what appeared to be non-violent crimes.

As the sting progressed, the officers tried to convince Buckley that they could help him with the cloud hanging over him because of his mother's death. He started by telling them that he didn't kill her, but he did discover her body.

The undercover officers told Buckley there was a biker in prison who owed Mr. Big a favour. They said the biker would confess to killing Buckley's mother but that he needed Buckley to provide explicit details of the killing in order to make his confession convincing.

Buckley said he had plenty of information about his mother's killing because he'd been provided with evidence by the Crown when he was charged with second-degree murder. Gang members told Buckley the Crown disclosure wasn't good enough, and that he would have to provide even more information.

Buckley eventually told the officers he snuck up behind his mother and struck her two or three times on the back of her head with a hammer.

In his decision, Arnold quoted this exchange between Buckley and one of the officers:

"John Buckley: I, I was there when it happened.

1: How do you know?

John Buckley: Because I did it.

1: Is, is that the truth?

John Buckley: Yeah."

The Crown had requested and was granted a publication ban to protect the identities of the officers involved in this sting because they are still conducting undercover operations.

The Supreme Court of Canada has imposed strict limitations on how confessions obtained through Mr. Big stings can be used. The biggest changes came from the case of Nelson Hart, a Newfoundland man accused of drowning his two daughters. Hart was initially convicted of two murders but those convictions were overturned on appeal.

As a result of that case, the Supreme Court of Canada ruled that the confessions themselves were not sufficient, and that additional corroborative information is needed in order to make the confession relevant.

• 'Mr. Big' sting confessions get stricter rules from Supreme Court

• 'Mr. Big' ruling a 'game changer' for those convicted in sting operations

In his decision on the Buckley case, Arnold said there was no additional evidence beyond the Mr. Big confession, which he ruled was too prejudicial for a jury to see.

Buckley talked about striking his mother with a hammer, but the murder weapon has never been recovered. Buckley even took police back to the scene of the crime to help search for the hammer. Arnold noted that while there, Buckley tried to escape, jumping into the ocean while handcuffed. He had to be rescued by one of the police officers.

In dissecting the evidence against Buckley, Arnold noted: "In his Mr. Big confession Mr. Buckley said that he had snuck up on his mother in sock feet, without shoes. This could not be independently confirmed. Mr. Buckley said he had used a hammer. This could not be independently confirmed. Mr. Buckley said hitting his mother with a hammer made a certain noise. This could not be independently confirmed."

The Crown has already served notice it is appealing Arnold's decision.