Senior Zimbabwe opposition leader Roy Bennett was killed late Wednesday with his wife and three others in a helicopter crash in New Mexico.
Police say the aircraft went down in a remote mountainous area in the northern part of the state, near the border with Colorado.
Another passenger who was injured in the crash survived and managed to call for help.
It is unclear what Bennett was doing in New Mexico.
The 60-year-old Bennett was treasurer-general of the opposition Movement for Democratic Change and a fierce opponent of longtime president Robert Mugabe, who was forced to resign late last year.
A party statement called Bennett "a resolute and committed fighter for democratic change in Zimbabwe."
Bennett, who was white, was admired by many black Zimbabweans who called him "Pachedu," which means "one of us" in the Shona language. He was known for helping hundreds of thousands of poor villagers pay for their children to go to school.