At issue is a quietly made ruling by the presiding coroner, Dr. William Lucas, that the family's lawyer cannot question the officers involved about discussions they had with their lawyer before writing their notes.
Provincial police Const. Jeff Seguin shot and killed Doug Minty, 59, in Elmvale, Ont., in June 2009. Police said Minty approached Seguin with an "edged weapon" he refused to drop, and the officer fired five shots.
Seguin was responding to a 911 call made by a door-to-door salesman, who reported that Minty had punched him in the face.
An inquest into his death began in November 2012 but was put on hold while lawyers for his family, and that of another man killed by police, battled in court over the issue of how the officers had prepared their notes.
Essentially, the family argued police involved in the shootings were effectively colluding by having their field notes vetted by the same lawyer before finalizing their notebooks and submitting them to civilian investigators.
Ultimately, the Supreme Court of Canada ruled in December in favour of the families, saying the involvement of lawyers was "anathema" to transparency and public trust in the note-taking process.
"Permitting consultation with counsel before notes are prepared runs the risk that the focus of the notes will shift away from the officer's public duty toward his or her private interest in justifying what has taken place," Justice Michael Moldaver wrote.
In requesting the cross-examination, Minty's family argued it needed to test the credibility of the officers and their notes had been compromised in light of the Supreme Court decision.
Nevertheless, Lucas ruled against the family, who wanted to cross-examine Seguin and a fellow officer, who arrived shortly after the shooting, about conversations they had with their lawyer.
"I find it would be inappropriate for the declaration by the Supreme Court of Canada to be applied retrospectively on these facts," Lucas said in his April 30 ruling.
He accepted Seguin's position that the conversations he had with the lawyer — at the time "well established practice" — were and still are privileged.
Lucas did say lawyers can test the credibility and reliability of the officers by usual cross-examination methods as long as they stay away from their discussions with their lawyer.
The inquest in Midhurst, Ont., is expected to last about four weeks and will hear from about 20 witnesses.
The provincial agency which investigates cases of death or injury involving police opted against pursuing any charges against Seguin.