Former US Vice-President Al Gore will not face charges over allegations he groped and assaulted a masseuse in his hotel room in Portland, Oregon, in 2006, law enforcement officials say.
The authorities say there is "a lack of credible evidence" and the claims do not warrant a criminal prosecution.
The decision comes a month after police reopened the investigation.
Mr Gore does not dispute that he had a massage from Molly Hagerty, 54, but denies any assault took place.
The case, which was closed previously because of a lack of evidence, was reopened in June after Ms Haggerty told the National Enquirer magazine that Mr Gore had tried to assault her.
Having reopened the case, prosecutors reportedly chose not to pursue it because Ms Hagerty had refused a polygraph test and appeared to have been paid by the magazine.
Mr Gore was in Portland to deliver a speech on climate change when the massage in question took place.
Mr Gore separated from his wife, Tipper, in June.