A man wielding a knife stabbed four people aboard a passenger train Friday, including an Amtrak employee, police said. The suspect, 44, of Saginaw, Michigan, was in custody and police said all four wounded people were taken to hospitals with varying degrees of injuries. Police were still trying to figure out what motivated the attack, AP reported. The train was traveling from Chicago to Port Huron, Michigan, and the attack happened at Niles, Michigan, about 100 miles (160 kilometers) east of Chicago.