A man visiting his daughter at Satun Hospital found a car key in the toilets and drove the car away, only to be arrested six hours later.
Satun Provincial police chief Pol Maj Gen Supawat Thapkliew announced the arrest of Chaiya Satan, 25, on Monday and alleged Chaiya had stolen a car belonging to Chamnian Tohlang, 38, the day before.
Both fathers had gone to the hospital to visit their daughters, who were being treated there.
Supawat said Chamnian forgot his car key in the hospital toilets and Chaiya had found it, managed to locate the car and driven it to a friend's house before returning to the hospital to see his daughter again.
Police quickly learned his identity from footage of the hospital's security cameras, however, and arrested him just six hours after Chamnian had filed his complaint.