POLICE are concentrating search efforts on trails in the New Territories for a Qantas steward who has been missing since August 3. Australian Walter Roos, 45, was last seen when he left the Marriott Hotel, Queensway. His disappearance was noticed when he failed to attend a staff meeting last Thursday. An avid hiker, he was due to return to Sydney on Thursday night as a passenger. Mr Roos is 1.72 metres tall, with medium build, grey hair and a dark complexion. He was last seen wearing a white tennis shirt, black shorts with red and pink piping, and a pair of white sports shoes.