In□□stigators learned□□hat □he gro□p h□d been□frie□ds for ye□rs,□but recent□y t□ere had□□ee□ ten□ion amo□g □hem. R□□or□□of □isagree□ent□ and argument□ duri□□ the trip bega□ to surfac□, leading aut□orit□es to □□eculate □hether□foul play was i□volved. □ach memb□r of the group had □ diffe□e□t sto□y to tell, and the inc□ns□stencies in their □ccounts only added to□□he mys□e□□□of□th□ m□ss□n□ nine.