There was a surge in transactions prior to the attacks of September that no-one has so far been able to explain. It has led to speculation that someone might have profited from previous knowledge of the terrorist plot by moving sums of money before the twin towers collapsed.

But because the facilities of many financial companies processing these transactions were housed in New York's World Trade Center, destroyed in the blasts, it has until now been impossible to retrieve the data.

That's where Convar Systeme Deutschland GmbH comes in. The company is helping reconstruct transactions from hard disk drives found in the ruins of the twin towers. Convar says it has an edge on competitors also working on the project: a laser-based scanning technology developed about two years ago.

The company is confident that it can reconstruct transactions from the data on the disks. "We were surprised how many disks were still readable", Convar’s director, Peter Henschel said.

"Not just the number of transactions, the amounts involved were staggering as well", according to Henschel. "It seems that someone was aware of what was about to happen and thought that computer transactions would go unnoticed amid the chaos" he said.

Convar is working closely with companies who had offices in the World Trade Center building.

"We are helping those companies to find out what was happening on their computers on September 11. And I am sure we will find out", Henschel said.