A scam linked to non-existent housing plots near east London's Olympic site has conned more than 100 people out of hundreds of thousands of pounds.
Fraudsters offered shares in companies supposedly owning land in Stratford which they said would "rocket" in value before the Games, police said.
Their victims could not contact them once their cheques had cleared, though.
Five men are due to be sentenced on 8 December for conspiring to defraud and a sixth for money-laundering.
"The lure was that they bought land around the Olympic site in 2006 and the price will rocket," Det Ch Insp Matthew Bradford, of City of London Police told BBC One's Inside Out programme.
"That was the hook to get people to buy land."
It was a "boiler-room" scam, he added, which meant it was carried out by "an organised crime group who use pressurised selling techniques to cold-call victims to try and get them to part with funds".
Their promotional material included quotes purporting to be from London 2012 chief Lord Coe talking about opportunities for development in east London.
Lorna Rapley said her late father, Alf, lost £37,500 in the fraud.
"He could phone them at any time night or day. He was really just drawn in by it," she said.
"They had websites that supported all of this; they were just very plausible and very nice-sounding."
Her father - who died in February - became "very reclusive" after losing so much money, Ms Rapley added.
"He felt he let everyone down."
John Middlemass, who lost £80,000 in the scam, said he was persuaded to join what "sounded like a good investment" by criminals who "ruined" his life.
"I spent 44 years working," he said.
"To lose all that money in the space of a couple of months doesn't even bear thinking about.
"That money was a nest egg that I could fall back on in a crisis and there's no money there now for anything."
In September Adrian Davison, 42, from Chislehurst, south-east London was convicted at Southwark Crown Court of four counts of conspiracy to defraud.
Andrew Bingham, 70, from Barking, east London; Patrick Goulding, 39, from Ashford, Kent; Kenneth Mullen, 42, from Kilmarnock, East Ayrshire; and Derek Voysey, 63, from High Wycombe, Buckinghamshire, were convicted of one count of conspiracy to defraud.
Christopher Fay, 64, from Blackheath, south London, was convicted of money-laundering.