I think it was a murder by the old school Kung-Fu masters for his disrespect, and being an outsider perverting the arts. He also stole sacred ground from the sacred Shaolin Temple in China. The theft can be seen on the season 3 Kung-Fu boxset in a recent video taped visit he had made to the temple. They killed Bruce Lee too. Just Kidding around. Most likely it was just some high priced (well connected) local hooker who panicked, and then left him like that. Then again, maybe after she got him all tied up like that, she pulled out and unrolled the old wanted poster in front of his eyes proclaiming, "Now the emperor has his revenge on you Kwai Chang Caine".