The Panama Papers put a much greater focus than ever before on a firm whose stock in trade is maintaining opacity for its clients—a strategy it has pursued for itself. Even within the world of attorneys who create shell corporations, Mossack Fonseca has been described, by The Economist in 2012, as “tight-lipped.” But a silhouette of the firm’s history can be drawn from reports and court cases over the years.

Mossack himself reportedly comes from a colorful family. His father, Erhard, moved the family to Latin America after World War II. The ICIJ reports that Erhard Mossack served in the Waffen-SS during the war. According to the ICIJ, U.S. intelligence files show he offered to spy for the U.S. government, possibly simply to shield himself. He later offered to spy for the CIA, from Panama, on Communists in Cuba. Süddeutsche Zeitung reports that Germany’s Federal Intelligence Service declined to hand over documents relating to Erhard Mossack due to possible security risks.

Jürgen Mossack’s practice only became Mossack Fonseca in 1986, when it merged with the tiny firm run by Ramón Fonseca, a Panamanian novelist, lawyer, and politician.

“Together,” Fonseca once reportedly told a journalist, “we have created a monster.”

That same year, 1986, according to the Panama Papers, Mossack learned he was involved in a front company for men who had robbed 3.5 tons of gold—£26 million at the time, and more now—from a Brink’s-Mat depot near London’s Heathrow Airport in 1983. “The company itself has not behaved illegally,” Mossack wrote in a memo copied to Fonseca. “But it could be that the company invested money through bank accounts and properties that was illegitimately sourced.” Instead, MF served as legal advisers to a new shell company created for Gordon Parry, who was on the lam and later served 10 years in prison for laundering money from the robbery. London’s Metropolitan Police had seized shares in the previous shell company, but under Mossack’s tutelage, The Guardian reports, Parry was able to outfox police by diluting the seized shares, then reconstituting the company.

That trick involved “bearer shares,” which seem to have become something of a MF specialty. A bearer share grants control of an instrument or company directly to whoever possesses a physical certificate. The ownership is not recorded or registered anywhere else. Bearer shares are banned in some countries because of the high potential for fraud and money laundering.

One place where MF took advantage of the possibilities posed by bearer shares was the British Virgin Islands. MF first expanded there in 1987; the BVI are now home to 40 percent of the world’s offshore companies, according to some counts. According to the Panama Papers, MF’s use of the tool grew steadily through the 1990s. But in 2005, the BVI cracked down on bearer shares, so MF simply switched that business to Panama. While MF’s use of bearer shares spiked sharply at home around that time, it since appears to have declined significantly.