Panamanian authorities raided a property used by Mossack Fonseca, the law firm whose leaked documents led to the 'Panama Papers' revelations.
"We have secured a large amount of evidence found in the location," said organized crime investigator Javier Caraballo, adding that some of the evidence was in the form of shredded documents.
The Panama Papers leaks have embarrassed several world leaders and shone a spotlight on the shadowy world of offshore companies.
Mossack Fonseca, which specializes in setting up offshore companies, has said it broke no laws, destroyed no documents and all its operations were legal.
The financial watchdog ordered banks and businesses to check whether they have links to a law firm at the centre of the Panama Papers leak.
In a letter to the European Council President in 2013 Mr Cameron argued offshore trusts should not be subject to new transparency proposals.
The nature of the tax avoidance carried out by Blairmore Holdings may have been misunderstood.