Counterterrorism police are helping to investigate the stabbing of 10 passengers on a train in eastern England on Saturday in what the defense minister said appeared to be "an isolated attack."Police, who arrested two suspects when the train made an emergency stop at Huntingdon, around 130 km north of London, said they will hold a press conference on Sunday morning as they seek to understand the circumstances and motivation.Defense Minister John Healey told Sky News on Sunday that there did not