On 31 December 1580, an associate of Lennox, James Stuart, Earl of Arran, son of Lord Ochiltree and brother-in-law of John Knox, had the daring to accuse Morton at a meeting of the council in Holyrood of complicity in the murder of Darnley, and he was at once committed to custody in Holyroodhouse and taken to Dumbarton Castle in the Lennox heartland. Some months later Morton was condemned by an assize for having taken part in Darnley's murder, and the verdict was justified by his confession that the Earl of Bothwell had revealed to him the design, although he denied participation, "art and part", in its execution.