In the late spring of 1646, the legal machinery of Perth turned its focus toward Geils Merser as she was brought before the authorities to face accusations of witchcraft. The records indicate that her case, filed under reference C/JO/2984, was formally initiated on May 20, 1646. This period in Perth was marked by heightened scrutiny of those suspected of diabolical association, and the procedural handling of the matter culminated in trial proceedings documented as T/JO/1255.
Geils did not face this process in total isolation; historical documentation suggests a potential link between her case and that of another local woman, Christian Gardner. The shared geographical proximity of the two women within the burgh of Perth may have contributed to the legal framing of their respective accusations. While the surviving records provide few details regarding the specific allegations leveled against her, the formal trial process serves as a somber reflection of the judicial climate in mid-17th-century Scotland, where individuals like Geils were subjected to the rigorous and often perilous scrutiny of the ecclesiastical and civil courts.