Seymour, a Grove City resident who served as a neighborhood drug go-between, was convicted of involuntary manslaughter and corrupting another with drugs after purchasing $15 worth of heroin for Adam, a recovering addict who died within an hour of injecting the drug in 2019. A forensic pathologist determined Adam died from acute intoxication involving heroin, kratom, Ritalin, and Benadryl, but could not identify which drug was primarily responsible for the death.
Writing for the unanimous court, Justice Hawkins emphasized that the state had presented sufficient circumstantial evidence to prove but-for causation, even without direct expert testimony pinpointing heroin as the sole cause. "Any rational trier of fact could—viewing this evidence in a light most favorable to the prosecution—readily conclude that but for Adam's taking the heroin on the day of his overdose, he would not have died," Hawkins wrote. The court noted that while the pathologist testified it was "extremely rare" to die from Benadryl, "very rare" to die from Ritalin, and "becoming more common" to die from kratom, "it was most common to see overdose deaths from heroin."
The court delivered some of its strongest language when critiquing the appellate court's analysis, declaring that "sufficiency-of-the-evidence review is not an exercise in scientific certainty." Justice Hawkins wrote that the Tenth District "misapplied the sufficiency-of-the-evidence standard of review" by focusing exclusively on direct testimony while ignoring compelling circumstantial evidence that "indicates that the heroin caused Adam's overdose death."
The case reached the Ohio Supreme Court after the Tenth District Court of Appeals reversed Seymour's convictions in 2024, concluding there was insufficient evidence that heroin was a "but-for" cause of Adam's death. The appellate court certified a conflict with the Third District's decision in State v. Carpenter, which had affirmed similar convictions in a mixed-drug overdose case. The Franklin County trial court had originally convicted Seymour on all charges following a bench trial.
The appeals court had rejected the state's arguments by requiring direct expert testimony that heroin alone caused the death, but the Ohio Supreme Court found this standard too restrictive. The court emphasized that evidence showed Adam had been sober for two years before obtaining heroin from Seymour, had appeared sober to his mother just before his death, and that toxicology revealed a "typical" heroin concentration for overdose deaths while other drugs were at therapeutic or non-toxic levels. "Evidence also suggested that Adam took the other, less dangerous drugs found in his system with some regularity," while "he had avoided heroin for years," the court noted.
Rather than adopting the state's preferred "substantial factor" test for causation, the court resolved the case under traditional but-for causation principles. Justice Hawkins explained that "the State need only prove that the death or serious physical harm would not have occurred absent the defendant's conduct" and "need not prove that the defendant's conduct alone would have caused death or serious physical harm." The court noted that "the existence of other necessary causes does not negate but-for causation."
The decision resolves a split among Ohio's appellate districts over how to handle causation in mixed-drug overdose prosecutions and provides clarity for prosecutors pursuing involuntary manslaughter charges in cases where defendants supply one of multiple drugs involved in a fatal overdose. The ruling emphasizes that courts must consider all evidence—both direct and circumstantial—when reviewing sufficiency challenges in criminal cases, potentially affecting how appellate courts evaluate causation evidence in future drug-related death prosecutions.