Ahmed spent some of the money in casinos and betting shops
A conman who tricked religious pilgrims out of hundreds of thousands of pounds has been jailed for six years.
Mohammed Faruk Ahmed pleaded guilty to using money meant for the Muslim pilgrimage to Mecca and spending some of it in casinos and betting shops.
Police say Ahmed conned at least 300 people in London's East End, many of whom devoted their life savings to the 2008 Hajj pilgrimage.
The Metropolitan Police is recovering some cash from accounts in Bangladesh.
Ahmed, of Brick Lane in London, was running a travel agency called Qibla Hajj Kafela Services.
He was offering to organise trips to the annual pilgrimage in Saudi Arabia - but was in fact preying on the local Bangladeshi community and Muslims in other parts of the country.
The 41-year-old took payments of almost £2,000 per client, amassing £570,000 from 300 victims.
Instead of using the cash to secure visas, flights and hotels in Mecca, Ahmed went on a gambling spree in casinos and bookmakers - and then fled abroad.
Meanwhile concerned pilgrims began calling the Metropolitan Police asking for help. They had received no travel documents and the deadline to obtain Hajj visas from the Saudi embassy was fast approaching.
Officers raided Ahmed's premises and discovered the 300 passports and paperwork showing £250,000 had been secretly moved from his business account to Bangladesh.
Detective Inspector Des McHugh of the Metropolitan Police told the BBC his team worked around the clock to ensure as many passports as possible were returned to victims so they could still submit them to the Saudi embassy for a pilgrimage visa.
"Ahmed shamelessly defrauded hundreds of innocent victims who had planned the most significant trip of their lives," said Det Insp McHugh.
"We worked hard to investigated the full scale of Ahmed's crime and officers placed themselves under additional pressure to process evidence and return passports to victims as soon as possible," he said.
Detectives eventually arrested Ahmed when he returned to the UK.
The £250,000 moved to Bangladesh had been frozen by court order, pending Ahmed's jailing. Officers are now finalising steps to return the cash to the UK so victims can make recovery claims.
"In many cases victims lost their entire life savings but still managed to retain their dignity and supply significant evidence to our investigation team," said Det Insp McHugh.
"Thanks to them and to a thorough police investigation Ahmed had no choice but to plead guilty," he said.