The coroner’s office asked one of the country’s leading pediatricians and toxicologists, Gideon Koren, to look at the case. Koren concluded that Jamieson had died after ingesting morphine through his mother’s breast milk—according to Koren, it was the first reported death-by-breast-milk case in history. He and a team of researchers later published a paper about the case in The Lancet, a prestigious international medical journal. It argued that, for some mothers with a certain genetic predisposition, taking even a mild dose of codeine could make their breast milk deadly.