National Lottery funding was used to set up a bogus charity as a front for committing armed robberies.
Officials were tricked into handing over £5,000 to the Buyaka charity, not knowing that the word means the sound of gunshots in Jamaican slang.
Orson De Silva claimed the money was to be used for underprivileged black males in Notting Hill, west London. But when police raided Buyaka's premises at Staples Corner, north London, they found plans for robberies, dye-stained fragments of money bags and a motorbike used for a getaway.
De Silva and six of his gang were convicted at the Old Bailey yesterday of conspiracy to rob and firearms offences. They will be sentenced later this week.
One of the gang, Antonio Bryan, 27, will also be sentenced for a series of gems raids in which more than £2m was stolen, including a £1.2m diamond ring.
De Silva, 27, Emmanuel De Silva, 39, Bryan, 27, David Samuels, 22, Keith Mason, 43, Nathan John, 23, and Ian Joseph, 29, all from west London, had denied carrying out a number of robberies which netted £95,000.
The National Lottery Community Fund confirmed it had been tricked and said it was investigating the circumstances.