Online gambling sites have been targeted by criminal gangs

Detective Superintendent Mick Deats, of the UK National Hi-Tech Crime Unit, said online crime groups can be more loosely linked and harder to track.

He added that online crime groups had become more noticeably professional over the last 18 months.

He was speaking at the E-crime Congress in London this week.

Crime spree

Mr Deats, deputy head of the National Hi-Tech Crime Unit (NHTCU), said that greater use of online shopping and banking was making the net a tempting target for organised crime groups.

"Where there's money there is organised crime," he said.

Information about the success of some organised crime groups broken by police operations reveal that in one case, the criminals made a total of �6m from phishing attacks.

Figures released by the NHTCU show how much cybercrime is costing the UK.

In 2004 fighting viruses cost �747m, beating off net attacks �558m and online fraud �690m.

Mr Deats said there were an estimated 70 organised crime groups around the world concentrating on net crime.

Big UK businesses lost more than �2.4bn to hi-tech crime in 2004, the NHTCU said.

Many firms that do a lot of trade online are also coming under attack from extortionists who threaten to knock a site offline unless they are paid a ransom.

"The more reliant a business is on the internet the more vulnerable they are," said Mr Deats. "And, quite frankly, many people pay."

Details about an operation against website attackers reveal that one gang made �1.3m in a 90-day period.

Some of the organised crime groups starting to use the net had the same rigid, hierarchical structure seen in offline gangs.

"In those situations we know who to target and who is in charge," said Mr Deats.

New species

But increasingly the net was making it possible for virtual groups to get together to commit crimes.

Online crime is proving lucrative for many people

Typically, said Mr Deats, these groups brought together people who were experts in particular fields.

"These tend to be loose groups of specialists," he said.

Some developed expertise in writing malicious code to steal confidential information or to mimic bank websites.

Others recruit and control 'bot nets - groups of hijacked home PCs that are used as spam and virus relays or to launch attacks on other sites.

"There are people that sell or hire their 'bot nets," said Mr Deats. "They are a marketable commodity in themselves, they are specialised and there are a lot of people doing that."

These technical specialists typically link in with criminals to help launder the cash they gather from phishing or ID theft.

"They all co-operate and interconnect and it's a difficult group to tackle," he said. "It can be difficult to work out who's in charge."

"They may never meet and there's no need for them to meet," said Mr Deats, "So it can be difficult for them to provide information you need to progress the enquiry."