<□>Investigators learned □□at the gro□p had □een □riends for ye□rs,□but recen□ly □here had □een tension among them□ Rumors o□ di□agreem□nts□and□arg□ments during□t□e trip □ega□ □o□s□rfac□, leadi□g authorities to □pecul□te□wheth□r foul □lay was □nvolv□d. Each member □f □he□group□had a □ifferent□sto□y□to tell□□and the□□nco□sistencies in□□heir□ac□ount□ only □dded to□the my□tery of the miss□□g nine.