Saying it's in the public interest and citing errors in law, Crown prosecutors have filed an appeal of the decision to stay charges against gangster Jamie Bacon in the Surrey Six murders.

B.C. Supreme Court Justice Kathleen Ker's decision earlier this month halted the prosecution of first-degree murder and conspiracy charges against Bacon in connection with the 2007 slayings of six people inside a Surrey highrise.

The B.C. Prosecution Service (BCPS) said Monday it has reviewed the ruling and found it "reveals errors of law."

"A reasonable argument can be made that the ruling would not necessarily have been issued if the errors were not made and … the public interest requires an appeal," the BCPS said in a press release.

Prosecutors are asking for Ker's decision to be put aside and for a new trial to be ordered.

Ed Schellenberg, 55, was in the apartment building to service fireplaces when he was killed. (CBC)

The reasons behind the stay are largely shrouded in mystery. However, an abbreviated ruling revealed that defence lawyers had somehow come to possess privileged information that affected Bacon's right to a fair trial but could not be used in his defence.

In part, Ker wrote, that situation "arose from the manner in which the police handled aspects of privileged and confidential information."

Little clarity on stay

The proceedings that led to the stay were conducted mostly out of the public eye, and apart from Monday's news release, prosecutors are not commenting on the stay decision, the appeal of that decision or any of the circumstances of the case.

The only new information unveiled by the Crown's choice to appeal the stay is that prosecutors did not agree to the judge's decision, according to Craig Jones, a law professor at Thompson Rivers University.

"It's quite extraordinary for a prosecution to be stayed except where the stay is requested by the Crown or consented to by the Crown," Jones told CBC News.

"Beyond that, we know precious little still about what the basis for it was, and I'm not sure that we'll learn much more on the appeal."

Bacon remains in custody on a separate charge of counselling the murder of an individual and has not applied for bail.

Setbacks for prosecution

Two other men are now serving life sentences with no chance of parole for 25 years in connection with the murders. Cody Haevischer and Matthew Johnston were convicted in 2014 of six counts of first degree murder and one count of conspiracy to commit murder.

The gangland hit ended the lives of six men, including four with criminal backgrounds and two innocent bystanders: 22-year-old Chris Mohan and 55-year-old Ed Schellenberg.

Chris Mohan, shown on a Facebook tribute page after his death, had recently moved to the same floor of the apartment building where the killings took place. (Facebook)

When news broke about the stay of charges against Bacon, Mohan's mother, Eileen, said she was outraged and called the judge's decision "unacceptable."

Premier John Horgan described the news as a "setback for all of us."

Prosecution of the murders has dragged on through the court system for years and has been complicated by allegations of police misconduct.

Four Mounties have been charged with breach of trust, obstruction of justice and fraud in connection with their investigation of the case; all were accused of sexual contact with protected witnesses.

With files from Ash Kelly and Anita Bathe