Somkid Changsalak, 41, was arrested at her house in Moo 8 village in Tambon Ban Mor, Prom Buri district, not long after the death of Saneh Wongdee, 38.
Somkid claimed that Saneh wanted her to test his mystic power, which he reportedly claimed had made his skin cut-proof. She said she used a 25-cm-long knife and stabbed him once on the back but it proved fatal.
Police, however, did not believe her account and charged her with murder.