B.C. Premier John Horgan says a court decision to stay charges against a man accused in one of the most infamous gangland killings in the province's history could compromise public trust in the justice system.

"We're going to work as aggressively as we can to make sure the public has confidence in our judicial system," Horgan said Monday. "This is a setback for all of us."

In a ruling that sent shockwaves around the province Friday, the B.C. Supreme Court stayed charges against Jamie Bacon in connection to the "Surrey Six" murders.

Bacon was accused of first-degree murder and conspiracy to commit the murder of 21-year-old Corey Lal, one of six people killed in a high-rise apartment building in Surrey in October 2007.

Two bystanders, Christopher Mohan and Ed Schellenberg, were among those killed in the execution-style massacre.

The reasons for Friday’s stay are sealed by the court, but an abbreviated ruling released by the judge says Bacon's lawyers had obtained information they were not allowed to use in his defence and could compromise his right to a fair trial.

"In part, this arose from the manner in which the police handled aspects of privileged and confidential information," the ruling said.

The judge also said the Crown cannot call someone Person X, whose identity is protected by a publication ban, to the stand during trial. In April of 2009, Person X pleaded guilty to three counts of second-degree murder and conspiracy to commit murder in connection with the killings.

Lawyers, politicians and the victims' families alike say they're surprised by the decision.

"Where's the justice in this?" said Eileen Mohan, Christopher's mother. "I just don't understand."

Defence attorneys for Matthew Johnston and Cody Haevischer—both convicted of first-degree murder in the killings—say the stay could help their clients by providing access to more documents from the Bacon case.

Both Johnston and Haevischer plan to appeal their convictions.

“I was surprised at that outcome. It’s exceptional for very serious cases and, in particular, murder cases to end in a stay of proceedings," said defence lawyer Brock Martland.

"I think our clients are hopeful that this will have a bearing on their appeal."

Neither of the convicted killers has a date set for an appeal hearing yet.

Bacon remains in custody as he awaits trial on a different charge. His trial is set to begin April 3.

Meanwhile, the families of the Surrey Six victims say the decision has reopened wounds they've spent the past decade trying to heal.

"Yes, Mr. Bacon has rights, but so does my son," Mohan said. "What about my son's rights?"

B.C.'s Attorney General David Eby says prosecutors are reviewing the Supreme Court decision to stay the charges to see if an appeal is possible.

In statement issued several hours after the ruling, Eby said he was "shocked" by the decision.

"I write these words today with tremendous disappointment," he said.

"The families of the victims and all who have been impacted by this terrible crime deserve peace, and they will not find it today."

With files from CTV Vancouver's Maria Weisgarber and The Canadian Press