Bout convicted in New York of selling heavy weaponry to Colombian rebel group Farc to help it attack US forces

A Russian arms dealer has been convicted of seeking to make millions of dollars by selling heavy weaponry to a terror group so it could attack what prosecutors said he told his customers was a common enemy — US forces helping the Colombian government.

A jury reached the verdict in the case against Viktor Bout after deliberating since Tuesday in federal court in Manhattan. He was convicted of conspiracy to kill Americans and US officials, deliver anti-aircraft missiles and aid a terrorist organisation.

Bout, a former Soviet military officer once known in the international arms market as the Merchant of Death, was arrested overseas in an elaborate sting in 2008. He had been transferred to the United States to face the allegations he sought to supply weapons on the black market to the Revolutionary Armed Forces of Colombia, or the Farc.

In secret negotiations with Drug Enforcement Administration informants posing as Colombian operatives, Bout "did everything he could to show he could be the one-stop shop for the Farc," assistant US attorney Brendan McGuire said in closing arguments.

Lawyers for Bout, 44, had offered what McGuire dismissively referred to as the "planes defence," claiming their client had no intention of selling any weapons but acted like he would so he could unload two old cargo planes for $5m.

Bout's attorney, Albert Dayan, argued that US authorities framed a legitimate businessman by building their case on recorded conversations that were open to interpretation and never resulted in the exchange of any arms or money.

US authorities "don't have anything," he said. "All they have is speculation, innuendo and conjecture."

The case began when Bout, while under United Nations travel restrictions, was approached in Moscow by a close associate about supplying weapons to the Farc. Bout was told that the group wanted to use drug-trafficking proceeds to pay for surface-to-air missiles and other weapons, making it clear it wanted to attack helicopter pilots and other Americans in Colombia, prosecutors said.

The associate, South African businessman Andrew Smulian, took the witness stand for the government as part of a plea deal and testified that Bout agreed that for a downpayment of $20m he would arrange for cargo planes to air-drop 100 tonnes of weapons into Colombia. Bout traveled to Thailand in March 2008 to finalise the phony deal with the two DEA informants.

One of the informants, Guatemala-born Carlos Sagastume, testified at trial about the secretly recorded exchanges with Bout in a Bangkok hotel room.

On one tape, an informant could be heard saying: "We want to knock down those American sons of bitches."

"Kill them, and kick them out of my country," the informant says. "They don't care where they go anymore. They go here, they go there. They go wherever they want. Why?"

Bout is quoted as saying on the tapes: "Yes, yes, yes. They act as if ... as if it was their home."

The witness said that during the same conversation, Bout was writing a list of weapons he could provide on a sheet of paper and at one pointed remarked: "And we have the same enemy."

Asked on the witness stand what that meant, the informant responded, "He was referring to the Americans."