The Department of Justice has launched a criminal investigation into tax avoidance following the massive data leak known as the “Panama Papers.” The leak revealed how the Panama-based Mossack Fonseca law firm set up a global network of shell companies for heads of state and other elites to store money offshore to avoid taxes and oversight. The leak revealed at least 200 U.S. citizens who used the firm to set up shell companies. The firm also set up more than 1,000 shell companies inside the United States—600 in Nevada alone.