A US expedition that voyaged to a remote Pacific island in the hope of solving the mystery of what happened to pioneering pilot Amelia Earhart has said an object they suspected to be her plane was a clump of washed-up trees.

“Unfortunately, we weren’t able to find that smoking gun,” said Steve Schultz of Purdue University, standing on the sand in front of a blue lagoon on the atoll of Nikumaroro, about halfway between Australia and Hawaii.

Earhart and her navigator Fred Noonan vanished in 1937 during their attempt to circumnavigate the globe at the equator, leading to one of the largest air and sea searches in history.…