Updated

The search for a 13-year-old Boy Scout who fell into the fast-moving Yellowstone River (search) was scaled back Monday as hope of finding him alive faded.

Tennis shoes believed to belong to Luke Sanburg (search) were found in the river over the weekend, but the math whiz who loved to hunt and fish remained missing after he fell into the river Friday.

"The family has come to the acceptance of not finding Luke alive," JeNae Lay, the boy's aunt, told rescue wmbers and other volunteers searched along the river's rugged banks for any sign of the missing teen.

Sanburg, of Helena, Mont., was pushing logs into the river with other Scouts on Friday when a log clipped his legs and knocked him into the river. He was last seen, head above water, floating toward a stretch of rapids, park officials said.

The boy's shoes were found about five miles downstream, one Saturday and the other Sunday. No other clothing was spotted, Matthews said.

Luke, who had just finished seventh grade, and six members of his troop were camping in the northern part of the park, about six miles from Gardiner, Mont., a park gateway. Three adults were with the boys.

The disappearance came just days after 11-year-old Cub Scout Brennan Hawkins (search) was found in good condition after spending four days wandering in the Utah wilderness.