Background
On the morning of April 6, 2017, a fire broke out in the basement of a Brampton-area residence where Brandon Aubin was the sole occupant. The Crown’s theory was that Aubin had been producing butane honey oil (BHO) — a concentrated cannabis extract manufactured using highly flammable butane — and that the discharge of butane vapour into the enclosed space ignited in a flash fire. The prosecution’s case rested primarily on the expert evidence of Jason Williams, an investigator with the Ontario Office of the Fire Marshal, who concluded that the fire’s characteristic flash pattern was consistent only with the ignition of a vapourised fuel, and that the physical evidence at the scene — empty butane cylinders, a BHO extractor, and trace amounts of cannabis resin — pointed to butane vapour as that fuel. Aubin admitted past involvement with BHO production and acknowledged entering the basement that morning, but denied producing BHO on that occasion.
At trial before the Ontario Superior Court of Justice (Justice Leroy, sitting without a jury), the defence had access to a report authored by Normand Matte, retained by the property insurer, which attributed the fire to a faulty extension cord connection to an aquarium light rather than to butane. Matte was qualified as an expert on a pre-trial voir dire, but trial counsel never sought Legal Aid Ontario funding to retain him as a witness and never called him at trial. The trial judge therefore ruled the Matte Report inadmissible. Nonetheless, exercising caution in light of the presumption of innocence, the trial judge used the Matte Report’s findings to rigorously test Williams’ conclusions before ultimately accepting Williams’ opinion and convicting Aubin on two counts of arson (Criminal Code, ss. 433(a) and 434) and one count of unlawful production of cannabis resin (Controlled Drugs and Substances Act, s. 7(1)).
Aubin appealed on a single ground: that trial counsel’s failure to seek Legal Aid funding for Matte (or a comparable expert) constituted ineffective assistance of counsel that caused a miscarriage of justice. Complicating matters, trial counsel passed away in September 2022 and could not explain his decision. The parties agreed on the key facts: counsel received Matte’s $12,200 cost estimate in March 2019, told Aubin and his mother legal aid would not pay and did not intend to ask, and filed no legal aid application for expert funding.
The Court’s Holding
Writing for a unanimous panel (Fairburn A.C.J.O. and Osborne J.A. concurring), Monahan J.A. dismissed the conviction appeal. The court applied the three-part test for ineffective assistance of counsel — factual, performance, and prejudice components — but resolved the appeal on the prejudice component alone, making it unnecessary to assess whether counsel’s conduct was actually incompetent. On the trial-fairness branch of prejudice, the court held that the alleged deficiency was discrete and isolated: there was no allegation of pervasive incompetence infecting counsel’s overall performance. Counsel had ably cross-examined the Crown’s expert (including by putting Matte’s conclusions to him), and Aubin had exercised his right to testify. The trial was not one-sided, and the failure to secure a reply expert did not amount to a constructive denial of the right to counsel or destroy the fairness of the adjudicative process.
On the reliability branch, the court agreed with the trial judge that even had Matte testified, there was no reasonable probability the verdict would have differed. The Matte Report suffered from two critical flaws. First, Matte had only inspected the fire scene two weeks after the fire, when it had been compromised by remediation work, and he lacked access to the Fire Marshal’s physical evidence. Second, and more fundamentally, Matte’s entire analysis assumed Aubin did not access the basement that morning — an assumption Aubin himself disproved at trial by admitting he had gone downstairs. That admission stripped Matte’s conclusions of their evidentiary foundation.
The court further noted there was no necessary inconsistency between the two expert conclusions: Matte identified the ignition source (a faulty extension cord) while Williams identified the fuel source (butane vapour). Both propositions could simultaneously be true — fire requires ignition, fuel, and oxygen, and identifying who introduced the fuel is the operative question for arson. Because Matte focused on ignition rather than fuel, his report did not rebut the central element of the Crown’s case. The sentence appeal was dismissed as abandoned, Aubin having served his sentence and filed no submissions on that ground.
Key Takeaways
- The prejudice component of an ineffective-assistance claim requires either pervasive incompetence undermining trial fairness, or a reasonable probability — not a mere possibility — that the result would have differed; a single discrete omission that does not infect the overall proceeding will rarely satisfy either branch.
- Where a trial judge, though unable to admit an excluded report into evidence, nonetheless rigorously tests the opposing expert’s conclusions against that report’s substance, the appellant’s ability to demonstrate prejudice from the report’s exclusion is substantially diminished.
- An expert opinion built on a key factual premise supplied by the accused is vulnerable to collapse if that premise is contradicted by the accused’s own trial testimony; courts will scrutinize whether such a report could realistically have altered the verdict.
- In fire-cause cases, the legally operative “cause” is the introduction of the fuel source, not the identification of the ignition source alone; experts who address only ignition may not meaningfully rebut evidence about fuel introduction.
Why It Matters
This decision reinforces the high threshold Ontario courts apply to ineffective-assistance claims arising from a defence counsel’s resource or tactical decisions. It confirms that appellate courts will not intervene simply because a different strategic choice — here, seeking legal aid funding for an expert — might conceivably have produced a better outcome. The case is a practical reminder that appellants must go further and demonstrate, through the lens of what the excluded evidence actually showed, that there is a reasonable probability the trier of fact would have reached a different conclusion.
The judgment also offers useful guidance on fire-causation evidence in arson prosecutions. By distinguishing between ignition sources and fuel sources as legally distinct elements of “cause,” the court clarifies that defence experts who focus narrowly on ignition without addressing the fuel source leave the core of the Crown’s theory intact. Defence counsel in scientifically complex arson cases should ensure that retained experts are instructed to address all necessary elements of combustion, and that the factual premises underlying any expert opinion are verified against the evidence that will actually be led at trial.