A Calgary jury heard today the man at the centre of a murder trial was the target of a major undercover police operation.

Kyle Ledesma is accused of shooting Dexter Bain at a pub in northeast Calgary in 2010. He was arrested 15 months later and charged with second-degree murder.

In its opening statement to the jury, the prosecution told the jury Ledesma was caught in what is called a "Mr. Big" undercover operation.

The prosecution said Ledesma confessed twice to killing Bain to police.

The defence says it's the validity of that confession that will be the central issue in this trial.

"Our client was the subject of a lengthy Mr. Big operation where at the end of the operation, he provided a confession about his involvement in this murder," said Rebecca Snukal, Ledesma's lawyer. "The message we are sending is that this is not uncommon, people falsely confess when they are under the influence of a significant police operation like a Mr. Big."

"That's what this case is about, it's about false confessions."

Bain was shot in the early hours of Nov. 27, 2010 at Our Place Pub and Grill in northeast Calgary.

According to his girlfriend at the time, Bain wasn't supposed to be there but had stopped by to help out the owners who were in the process of selling the pub.

Police believed at the time that it was a botched robbery, as Bain had no connections to criminal activity.

The prosecutor says Ledesma's DNA was found on a gun that is believed to be the murder weapon.​

The trial is set to last four weeks. The prosecution says it will call about 50 witnesses.