Ivan Barc, of Barc and Co, Wood Green, was jailed for two and a half years after police used computer evidence to show that he had concocted fictitious company accounts.
Hampshire police proved that Barc was supplying the accounts to a gang which used them to fraudulently claim credit finance to buy fleets of expensive cars.
Forensic investigator Kevin Reid, who runs security firm DataSec, recovered deleted copies of accounts from Barc's office PCs which matched the fraudulent accounts supplied to finance companies.
Reid used forensic search discs to show that the machines' hard drives were likely to contain evidence and could be seized by the police.
The fraud came to light after a finance company help-line operator noticed similarities in accounts submitted by different firms to support finance applications.