A former Tajik minister, Mirzo Ziyoyev, who allegedly joined a drug-trafficking gang, has been shot dead by his new comrades, officials say.
The Interior Ministry said he was arrested on Saturday and then agreed to reveal the gang's hidden weapons and negotiate the surrender of its leader.
But a gun battle erupted at the talks, killing Ziyoyev and wounding several officers, Tajik officials said.
Ziyoyev was a powerful rebel commander in the 1990s Tajik civil war.
The five-year war pitted the Moscow-backed government against a mostly Islamist opposition, of which Ziyoyev was a key player.
He was appointed the emergency services minister as part of a power-sharing agreement in 1997, but was dismissed three years ago.
Tajik officials said he was arrested on Saturday in connection with an armed attack on a police post in the eastern Rasht Valley, close to the Afghan border.
The other members of the group included a Tajik Islamic fighter and five Chechen nationals. They have been taken to the capital Dushanbe for questioning, officials told Reuters news agency.
The Rasht Valley - a former opposition stronghold - had been sealed off since May for what the Tajik authorities say is an annual anti-narcotics operation.
But some independent observers say the government is fighting armed militant groups that include foreign fighters, according to the BBC's Central Asia correspondent Rayhan Demytrie.