Twelve passengers arrested after a Northwest Airlines flight returned to Amsterdam’s Schiphol Airport on Wednesday amid a security alert are still being held. Police at Schiphol detained them after the DC-10 aircraft was forced to return to Schiphol - flanked by two F16 fighter jets - shortly after taking off. The pilot asked for permission to return to Amsterdam for ‘security reasons’. The plane, with 149 passengers on board, was on its way to the Indian city of Mumbai. (...) A number of passengers explained afterwards that a group of men of ‘Asian’ appearance had boarded the plane very late. They appeared to be Muslims - a few of them had beards - and one of them reportedly had a guitar case with him. The group are said to have paid no attention to the safety instructions.