An autopsy on a California woman who disappeared during the Rainbow Family gathering has failed to determine her cause of death.

Skamania County Undersheriff Dave Cox says authorities might never know how Marie Hanson, 54, died. Cox told The Daily News Friday that determining what happened to Hanson will be difficult without forensic evidence.

The South Lake Tahoe woman traveled to Gifford Pinchot National Forest with neighbors for the gathering. A witness said Hanson was last seen leaving with a man July 6.

The Associated Press