President Bush: Freezing the assets of terrorists

"Now you have to understand that every banker who touched this money - if he did it knowingly or did it by putting a bag over his head and acting like he didn't know about it - is a co-conspirator and ought to be treated as such," said Mr Blum.

He alleged that many of the people involved in backing the 11 September attacks were probably once connected to the failed Bank of Credit and Commerce International, which allowed Middle Eastern countries to support extremist fighters in the region.

And he said that the world should force Dubai to reform, as offshore havens in the Caribbean have been forced to do.

Collaboration

Opening the conference, the Royal Canadian Mounted Police's commissioner, Giuliano Zaccardelli, said that since criminal organisations have gone global, law enforcement had to do likewise.

"In a way sometimes I'm envious of how (criminal groups) collaborate and work," he said.

"To succeed, we not only have to adapt some of those strategies, we have to do it even better."

There are signs, according to John Mair, an RCMP investigator, that some of these countries are responding more positively since last month.

But so far there have not been any publicised successes in tracking down the financial roots to those involved in the attacks.

That may be an indication of the size of the task, or reluctance by investigators to reveal how much they know already.