Apostle Accounting: Police investigate Suffolk accountancy firm
Police said officers were investigating "a large number of allegations of fraud" involving an accountancy business.
The BBC found dozens of workers who used Apostle Accounting to apply for HM Revenue and Customs (HMRC) tax refunds were told to repay the money.
Suffolk Police said it was liaising with HMRC and other agencies.
Apostle Accounting had earlier told the BBC that it had done nothing wrong and blamed HMRC.
"Suffolk Police have been made aware of a large number of allegations of fraud involving a business in Stowmarket," said a force spokeswoman.
"An investigation is now under way, and officers are liaising with HMRC and other agencies."
A group of MPs has written to HMRC calling for an investigation, saying that it had caused "a great deal of anxiety and stress among many of our constituents".
'Unfounded'
Some people have been told to repay thousands of pounds by HMRC because they had made incorrect claims and were not entitled to the money.
In an earlier statement issued through its lawyers, Apostle Accounting, based in Stowmarket, denied any errors and said claims were "unfounded".
It denied any allegations of "non-compliance issues and/or fraudulent tax claims".
The firm said it sought its own independent tax advice, which found no evidence that claims were made on behalf of customers without their knowledge.
They added HMRC had reviewed Apostle's approach to these expense claims in 2019 and found it to be acceptable.
Apostle said its advisers also felt the HMRC's actions appeared to be wrong, outside the law and its own guidance.
Previously, HMRC said: "You should treat promises of easy money with real caution - if it sounds too good to be true, it probably is."
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