It was a ‘bargirl’ with whom he had met at least two times before. In this occasion she tried to drug and rob him, claiming that he refused to pay her. She drugged him but it appeared to not have the desired effect, so two of her ‘friends’ came in to finish the job… so claims the culprit: https://thethaiger.com/hot-news/crime/suspect-says-he-stabbed-chinese-businessman-to-death-in-south-thailand