TORONTO - Allowing an investigative report on alleged police misconduct to be used at an inquest could taint criminal proceedings against an officer as well as pending Police Services Act charges, an inquest into a teen's death heard Tuesday.

In addition, the Office of the Independent Review Director said use of its report could lead to a "chilling effect" on the participation of complainants, witnesses and officers in probes of complaints against police.

"This, in turn, will have a negative effect on the (director's) ability to fully and fairly investigate a public complaint," director Gerry McNeilly said in written submissions.

More importantly, he said, findings of misconduct can only happen at a hearing where evidence is called, witnesses are examined and cross-examined, and submissions are made.

"Accordingly, the (director) has concerns about the investigative report being admitted for its truth," McNeilly said.

The report in question urges disciplinary charges against Const. Michael Adams and four other officers over the "discreditable" arrest of Adam Nobody at the turbulent G20 summit in June 2010.

Nobody suffered a fractured cheekbone and nose.

The family of Junior Manon, 18, of Toronto, who died seven weeks before Nobody's arrest, says the report is relevant to the inquest into his death.

The teen suffocated during his arrest May 5, 2010, following a traffic stop in which Adams and another officer were involved.

Manon's family, which is also suing the Toronto police force, argues evidence concerning Adams' use of force against Nobody and Manon "may demonstrate a systemic failing" in how police are trained and supervised.

"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.

"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."

Julian Falconer, who represents the Manon family, told the hearing he would be content to cross-examine Adams on the contents of the report and its allegations rather than have the entire report entered as evidence.

Like McNeill, Adams' lawyer Gary Clewley urged presiding coroner, Dr. Dan Cass to reject the family's request.

"This motion is an invitation to travel down the route of irrelevance and will sidetrack the (coroner's) jury," Clewley said in his submissions.

Clewley noted that Adams had not yet been tried under the Police Services Act, and that the province's Special Investigations Unit found no grounds to charge anyone criminally in Manon's death.