A ninth man arrested is now being questioned by immigration authorities. None of the men have been charged.
The arrests were sparked after checks by the Big Lottery Fund uncovered anomalies in community group grants.
False applications had been used to defraud the charities, it was thought.
Charity regulator The Charity Commission has also launched an investigation into the allegations, which were believed to have involved hundreds of thousands of pounds.
It has frozen around 30 bank accounts, all thought to be in England and Wales, “to protect charitable funds”.