An independent review into the handling of historic fraud allegations against Lloyds Bank has been shown new documents said to allege a "major fraud" may have been committed.
Several business owners alleged they have been ruined by the firm's business support unit based in Bristol.
Avon and Somerset Police said it had found no evidence any criminal offences had been committed.
But up to 200 alleged victims say their claims were not properly investigated.
Last year, Avon and Somerset Police asked Thames Valley Police to conduct a review into allegations made against the financial institution.
Thames Valley police and crime commissioner (PCC) Anthony Stansfeld oversaw the successful prosecution of corrupt financiers from HBOS in Reading for a multi-million pound loans scam that destroyed several businesses.
Thames Valley Police officers have now interviewed one alleged victim, property investor Kashif Shabir, whose documents were not passed to them by the Avon and Somerset force.
Mr Stansfeld has written to the Avon and Somerset crime panel stating the documents "strongly indicated that a major fraud" had been committed against Mr Shabir.
'Different complexion on things'
The PCC added: "Thames Valley Police did not investigate the cases, and if evidence was withheld by Avon and Somerset, it would put a wholly different complexion on any findings."
Dr Kirstie Cogram of Avon and Somerset Police's complex crime unit, said: "Thames Valley Police, during the course of its review, spoke to individuals who made the allegations and were given a small number of documents not before seen by Avon and Somerset.
"We received them in late January and having looked into these we have concluded they do not show any evidence of criminal wrongdoing."
A Lloyds Banking Group spokesperson said "Lloyds Bank have always strongly denied any wrongdoing in Bristol and that Mr Shabir's claims have been reviewed and found to be baseless."