Six Vietnamese tourists whose bodies were found at a Bangkok hotel died from cyanide poisoning in a suspected murder-suicide, according to Thai investigators. A dispute over large debts is believed to be the motive. At a briefing on Wednesday, officials from the Metropolitan Police Bureau said traces of cyanide were found on six tea cups and a water container in the room where the bodies were found. There is no evidence that anyone else entered the room. “There are no other possibilities. The culprit is among the six because they were the only people who entered the room. There were no others,…