As such, the family wants to introduce a new report by Ontario's police watchdog that found Const. Michael Adams used excessive force in an unrelated arrest seven weeks after the death of Junior Manon.
"Whether Const. Adams had a propensity to use excessive force is relevant to the jury's assessment of the evidence, including whether Mr. Manon died by means of 'homicide' or 'accident'," according to the family's motion, slated for argument Tuesday.
"Without the benefit of hearing evidence on Const. Adams' use of force in respect of Mr. Nobody, the inquest will be deprived of evidence which is central to its social and preventative function."
The inquest under Dr. Dan Cass is looking at the death of Manon, 18, of Toronto, who died after Adams and a second officer arrested him on May 5, 2010.
An autopsy concluded that Manon suffocated when the officers restrained him after a short foot-chase that followed a traffic stop.
"The mechanism of death was the reduced ability to breathe due to restriction of chest movements during prone restraint with added weight on the back," according to the autopsy report.
The autopsy ruled out substance abuse or "excited delirium" as contributing to this death.
Seven weeks after that incident, Adams was one of five officers involved in what the Independent Review Director — who looks into complaints made against police — decided was the "discreditable" arrest of Adam Nobody during the G20.
The director is calling for Adams and the others to face Police Act charges for the arrest, which left Nobody with a fractured cheekbone and damaged nose.
Manon's family, which is suing the Toronto police force, argues in written submissions that the coroner should admit the director's report as evidence and allow them to cross-examine Adams on its contents.
"The jury is entitled to assess Const. Adams' evidence concerning his use of force against Mr. Manon in the context of his strikingly similar account of his use of force against Mr. Nobody," their motion states.
"The evidence concerning Const. Adams' use of force against Mr. Nobody (and Mr. Manon) may demonstrate a systemic failing in the manner in which Toronto Police Service officers are trained and supervised."
Adams' lawyer Gary Clewley said Monday he would urge the coroner to reject allowing the report as irrelevant.
The Manon family can thrash the matter out either during its civil suit or when Adams faces Police Act charges for the Nobody arrest, he said.
"The coroner's jury is not there for that purpose," Clewley said.
The province's Special Investigations Unit found no grounds to charge the officers criminally in Manon's death.
Documents show the officers told the SIU that they did not apply any pressure or force to Manon's back or chest during his restraint.
Adams also told the SIU he punched Manon as "distraction strikes" because the teen was "wild" and aggressive and he was "scared" they would be unable to control him.
"Their accounts are contradicted by numerous civilian witnesses who report that the officers were on top of Mr. Manon during the restraint," the family argues in written submissions.
"In addition, civilian witnesses report that the officers placed Mr. Manon in a headlock or neckhold, and that one of the officers repeatedly struck Mr. Manon in the head with a police radio."
The family also notes the complaints director rejected Adams' argument he had to use force against Nobody because he was violently resisting arrest.