OTTAWA -- Allowing police officers under investigation by watchdogs to consult with lawyers before preparing their notes is an "anathema" to transparency and public trust in that process, the Supreme Court of Canada ruled Thursday.

The high court ruling, by a margin of 6-3, pitted officers against the families of two men shot dead by Ontario's provincial police in separate incidents in 2009.

The ruling offers clarity to the regulations that govern the Ontario's Special Investigations Unit, which investigates violent incidents involving police officers.

"First, consultation with counsel at the note-making stage is antithetical to the dominant purpose of the legislative scheme because it risks eroding the public confidence that the SIU process was meant to foster," wrote Justice Michael Moldaver for the majority.

"A reasonable member of the public would naturally question whether counsel's assistance at the note-making stage is sought by officers to help them fulfil their duties as police officers, or if it is instead sought, in their self-interest, to protect themselves and their colleagues from the potential liability of an adverse SIU investigation."

Lawyer Julian Falconer represented the families of Doug Minty, 59, and Levi Schaeffer, 30, who were shot and killed by Ontario Provincial Police officers in separate incidents in June 2009. He said the ruling is a victory for the families, but the cycle of police using guns on emotionally disturbed people must be broken.

"There is a recognition, a historical recognition, that the police use of lethal force, when they take the lives of mentally disabled men such as in this case, when they take the steps they do, it has a profound impact on our social fabric," Falconer said after the ruling was issued.

"For that their price, their responsibility, is to be undeniably and absolutely accountable and it is sad that these families had to bear the burden, the task, of getting this job done. It shouldn't have fallen to them."

The "indispensable foundation" for the significant authority entrusted to police is public trust, and that trust can be tested when a member of the community is killed at the hands of a police officer, Moldaver wrote.

"The SIU is charged with the delicate task of determining independently and transparently what happened and why, in the hope of providing the community with answers," he wrote.

"Permitting police officers to consult with counsel before their notes are prepared is an anathema to the very transparency that the legislative scheme aims to promote."

The families spent the past four years arguing that having a lawyer approve the notes that end up in police memo books is unacceptable. Ruth Schaeffer said she spent her life savings on the case.

"It's a significant and necessary step on the way to ensuring accountability from the public servants in Ontario who have the most extraordinary powers," she said.

Evelyn Minty said it has been a long, hard road, but she and her family did it for Doug and for "future families who need honest reports wrote up by the police." There isn't a day that goes by that she doesn't think of her son, she said.

"I must admit I've had help from my family," Minty said, choking up. "I've had help from my friends and when the going gets bad, I cry. Nobody knows. Sometimes at night in the dark of night."

Police argued they have the right to talk to a lawyer of their choosing before finalizing their notes.

Three Supreme Court justices dissented, arguing that everyone has the right to consult with a lawyer.

"This freedom reflects the importance of the societal role of lawyers in a country governed by the rule of law and it should not be eliminated in the absence of clear legislative intent," they wrote.