Many do not know about scams from some online job searches
Police chiefs are urging people looking for work during the recession to be alert to online scams that trick them into laundering money.
The Serious Organised Crime Agency (Soca) says websites are currently being used to recruit "money mules".
The "mules" are ordinary people who send and receive payments through their bank accounts to facilitate business.
But in reality, the cash has been laundered from crime, leaving unwitting mules open to prosecution.
The warning comes at the beginning of the annual Get Safe Online week, a campaign jointly run by government, law enforcement agencies and industry to alert people to the dangers of fraud on the internet.
According to the campaign, fraudsters are using a variety of bogus and legitimate recruitment channels to con job-hunters into thinking they have found genuine employment.
TIPS FOR JOB-HUNTING ONLINE
Do a search for the company address
Do a Post Office address look-up for the company address
If the employer asks to use your bank account, end your interest in the position
But in each case the job comes down to asking the victim to receive relatively small amounts of money into their own account and then move them onwards to another bank.
Official figures suggest there was a 55% rise in online banking fraud in the first half of 2009, equal to £39m in losses.
That money inevitably needs to be laundered through the system so that it cannot be linked to the criminal networks behind the original theft.
But Get Safe Online says its survey found that that nine out of 10 people had never heard of money mule scams, despite widespread use of the internet to find work.
Sharon Lemon, deputy director of Soca's e-crime division, which provides a strategic lead in combating online fraud in the UK, said: "Criminals are reliant on mule operations to receive and forward money taken from online banking fraud.
"Some money mules know exactly what they are doing. However, many end up unwittingly laundering profits for overseas criminals as a result of being taken in by fake recruitment sites.
"The consequence is that they end up liable for all the criminal funds they've received - which must be repaid, their bank accounts are frozen and they may be subject to criminal investigation."
Tony Neate, head of GetSafeOnline.org, said: "At any given time, there are approximately 100 known mule recruitment sites targeting the UK, each of which may have around 50 active mules.
"Many will be moving considerable sums of money, but even based on a low estimate that each mule makes just three to four transactions, amounting to around £1,500, before being caught - that's already £7.5m in illegal funds.
"Fraudsters go to great lengths to convince potential mules that they are applying for a genuine job - some even issue official-looking employment contracts for their 'employees' to sign.
"Many mules are unwitting accomplices; they are the easiest part of the criminal chain to track down."