A multi-year U.S. intelligence review has deemed it “very unlikely” that a foreign adversary is behind the mysterious neurological symptoms known as “Havana Syndrome” that have been reported by more than a thousand American officials since 2016, eliminating a leading theory shared by some victims and lawmakers that U.S. personnel were being targeted by a hostile government. 

The unclassified assessment, released Wednesday by the Office of the Director of National Intelligence (ODNI), reflected the views of seven agencies that participated in the inquiry.

“Most [intelligence community] agencies have concluded that it is ‘very unlikely’ a foreign adversary is responsible for the reported AHIs,” the assessment said, noting different agencies had varying levels of confidence in the finding.

Five of them found that “available intelligence consistently points against the involvement of U.S. adversaries in causing the reported incidents,” according to the assessment.

“Most IC agencies judge it is very unlikely a foreign adversary played a role, although confidence in the judgment related to this line of inquiry varies, with two agencies having moderate-to-high confidence; three agencies having moderate confidence; and one agency abstaining,” the assessment said. “One agency judges it is only unlikely a foreign adversary played a role and has only low confidence in this judgment.” 

Briefing reporters at ODNI headquarters on Wednesday, two intelligence officials laid out the results of what one described as an “historic” level of expertise and resources dedicated to the inquiry. Investigators reviewed more than 1,500 reported cases from 96 countries, including some reports made this year. 

This is a breaking story. It will be updated.