By Steve Lambert, The Canadian Press WINNIPEG - Manitoba RCMP had no answers Thursday as to what prompted a man on a Greyhound bus to suddenly stand up and repeatedly stab his seatmate, behead him and carve up his body in front of horrified passengers. Police would only say that a victim was stabbed on the bus that had left Edmonton for Winnipeg, but passengers described a gruesome, unprovoked attack that left them shaken. ((My first news post I hope I did it right if not have mercy,.,))