The captain of the Danish fleet averred that the storms had been caused by the wife of an administrator who he had insulted. The seriousness of the threat to the King's life meant that investigations were prompted into witchcraft.
Suspicion soon fell on the inhabitants of the town of North Berwick where a maid, Gelie Duncan, had long been suspected of supernatural abilities due to her ability to heal the sick. Her master, Chamberlin David Seton, oversaw her torture where eventually she confessed to being part of a coven of 200 witches in the town, who met on the site of the Auld Kirk on Hallowe'en to meet and receive sermons from the Devil himself. She also named a number of other locals as part of the coven - including John Fians, a schoolteacher from nearby Prestonpans.
Under torture, Fians further implicated witches in the fate of James' fleet as well as the Earl of Bothwell - although he recanted his accusations and confession at his execution.
Ultimately, around 70 people are thought to have been executed throughout the two year investigation.