Briton Hemant Lakhani has been found guilty of attempting to support terrorism, after trying to sell a shoulder-launched missile to an undercover FBI agent.
Lekhani inspects the replica missile
The 69-year-old, of Hendon, north London, had denied the charges, saying he was a victim of entrapment
The BBC News website looks at the background to the case.
In 2001 Hemant Lakhani, an Indian-born British businessman living in Hendon, north London, went to Dubai to look for financial backing for a £130m deal on an Indian oil-refinery project.
While he was there, a contact encouraged him to speak to a rich Saudi friend who could help.
The friend was Mohammed Habib Rehman, also known as Air Haji, an undercover US Government informant.
The pair began conversations in December 2001.
Mr Rehman told Lakhani he represented a rebel Somali liberation group and was interested in arms - in particular shoulder-fired missiles.
Lakhani, who was eager to please his new contact, said he would try to help.
He had previously made one arms deal, which was the legal sale of 11 armoured personnel carriers to the government of Angola.
To make the deal for Mr Rehman, Lakhani received help from a man called Sergi in the Ukraine. Lakhani has claimed Sergi was working for Russian intelligence.
Sergi said he could supply Lakhani with Russian-made shoulder-fired missiles, called Igla.
When Lakhani told Mr Rehman he could get hold of the missiles, Mr Rehman instructed him to export the weapon to New Jersey, promising cash.
Mr Rehman said he would buy 200 weapons - a deal worth £11m, but told Lakhani to ship in one sample missile to begin with.
The two later met up at a hotel overlooking Newark airport in New Jersey. Mr Rehman explained to Lakhani that the deal was illegal.
He also told him he planned to use the missiles on the first anniversary of the 11 September attacks, and suggested the missile would be used to target a commercial aircraft.
However as time went on, Lakhani began to make remarks about the risks they were taking, saying the deal was "very dangerous" and "not very easy".
In November 2002, he told Mr Rehman: "This business is getting so dangerous. No one has the guts to do it... I won't do anything if it's risky."
Despite the risks, the plans eventually took shape, and in July 2003 Lakhani and Mr Rehman travelled to Russia, under the watch of intelligence agents, to meet with the suppliers and inspect the missile.
But unknown to Lakhani, the missile had been replaced with a replica model.
On August 12, 2003, the missile was delivered to Newark. Lakhani met Mr Rehman there to inspect the weapon, saying: "I can't believe what we have done."
After discussing payment for the remainder of the order, Mr Rehman left the room.
It was then stormed by FBI agents and customs officials.
Lakhani was charged and then placed in custody in New Jersey until his trial, which began in January 2005.