The City of London Police said yesterday it is considering whether to refer Wonga to its national policing lead for the crime after meeting officials from the Office of Fair Trading [OFT].
It came hours after the Law Societies in England and Wales, backed by their Scottish counterpart, urged the police to consider a criminal investigation into the controversial firm, which is to pay £2.6 million over its actions.
A spokesman said: "In March 2013 the Office of Fair Trading met with the City of London Police to consider their (OFT's) investigation into Wonga and whether it should be referred to the National Policing Lead for Fraud.
"The interests of the consumer were at the forefront of these discussions and directed the decision that the most appropriate course of action was for the OFT to continue to investigate as regulator focusing on but not limited to the consumer credit act, legal services act, and unfair trading regulations.
"Now that the regulator's investigation has concluded and a compensation agreement has been reached with Wonga, the City of London Police will be reassessing whether a criminal investigation is now appropriate."
The Law Society in England and Wales had already stepped up pressure for a criminal investigation to be held into Wonga.
It was backed by the Law Society of Scotland, although there is no direct evidence that any of the letters came from fictitious Scottish law firms.
Chief executive Lorna Jack said: "It is a criminal offence to impersonate a solicitor.
"We always take action whenever we believe anybody is misleading people by holding themselves out in this way.
"While we have no direct evidence that any of the letters sent by Wonga were from impersonated Scottish solicitors, we would expect that the authorities here in Scotland would look into any potential criminal act and liaise with English colleagues where necessary. "