The structures, allegedly created by Mossack Fonseca, typically included a sham foundation that owned the shell companies, which in turn held the undeclared assets on behalf of the US taxpayer. The clients' names did not appear anywhere on the incorporation paperwork. In the scheme set up for Goltz, it was falsely claimed that his elderly mother, a Guatemalan citizen and resident, was the sole beneficial owner of the shell companies and bank accounts at issue.

The bank accounts were set up in jurisdictions with strict bank secrecy laws, and the cash in them was typically repatriated to the US using debit cards and fictitious sales.

The penalties being sought by the US Department of Justice for tax offences range from five to ten years in prison. However, charges of money laundering and 'wire fraud' are also being pressed, which could take the maximum sentences to 20 years.

The Department of Justice press release reveals it also investigated two more Mossack clients, referred to as Client-1 and Client-5. However, they entered the Internal Revenue Service's offshore voluntary disclosure programme in 2013, before the Panama Papers disclosures. It is not clear whether they too will be charged.