A man was found hanged in his bedroom in Prachin Buri's Prachantakham district late on Tuesday night after he made a video call to his Thai girlfriend in Japan.
Phon Ruangnam, 51, was found dead by his sister in their house in Moo 6 village in Tambon Nong Kaew shortly before midnight.
The sister, Sangwian Ruangnam, 60, told police that she took a phone call from a friend of her brother's girlfriend, warning that something might be wrong. Sangwian rushed to check Phon's bedroom and discovered he had hanged himself with a nylon rope.
The girlfriend had raised the alarm after Phon threatened to hang himself, at which point she heard the phone fall and there was silence.
Sangwian said she had no idea why her brother would want to commit suicide.