In the first year of his employment, a woman who was set free from charges of sorcery, was threatened that if she was ever accused again, Håkan would expose her to the ordeal by water; two years later, he performed this test on two women in Jönköping - possibly the first time this method was used in Sweden - and in 1594, he was highly recommended for having exposed a woman called "German-billa" and making her admit to sorcery.
These first trials are badly documented, but few of them led to a death sentence - most of those accused before 1608, such as Kristin of Hultaby in 1604 and Karin Månsdotter in 1605, were either cleared of the charges, or, if judged guilty, whipped rather than executed.
In 1611, Elin was put on trial in Sunnerbo, and Håkan was called upon to expose this famous witch, ten years after their first encounter.
She was accused of a long list of charges; she had practised love-magic on the fiancee of her sister, Simon Thuresson, when he contemplated breaking off the engagement; she had murdered both her first husband Niels Pedersson and Maretta Laressa by use of magic; she had made cattle sick by sorcery and then taken money to make them healthy again, and she had used enchanted hares to suck milk out of other people's cattle and bring it to her.
She had had an argument with her former father-in-law, (the father of her first husband), in which he accused her of having murdered his son for the inheritance, and made her former brother-in-law sick when he tried to make peace between them.
He had asked to observe her without her knowing it, before she was told that he had been hired to perform the investigation, and he claimed that he saw the mark under her breast despite the fact that she was fully clothed at the occasion.
This is regarded as a strong indication that he had seen her naked before, and that he had helped her to pass the test during the first trial because he had been bribed with sexual favors; had she known he was there, she could have revealed this.
Master Håkan continued with his persecution of witches until his death in 1638; he handled the trials of Britta Arfvidsdotter in 1616 and Ingeborg Boggesdotter in 1618, who were both executed for sorcery in 1619.