Mr Brodsky is best known for his time in the US Attorney’s office, during which he led the 2011 insider trading prosecution and conviction of hedge fund giant Raj Rajaratnam, as well as former Goldman Sachs director Rajat Gupta in 2012.

‘Ponzi scheme’

Gibson Dunn partner Joel Cohen and counsel Lisa Heather Rubin have also filed a notice of appearance alongside Mr Brodsky indicating they will represent Mr Greebel. Mr Greebel served as lead counsel to Retrophin from December 2012 to September 2014 and has been accused by US prosecutors of assisting in a number of financial transactions in which ‘Shkreli essentially ran his company like a Ponzi scheme.’

Internal investigation

Mr Greebel, who was a partner at Katten Muchen Rosenman at the time of the alleged fraud, has until now been represented by Jonathan Sacks of Morvillo Abramowitz. He joined Kaye Scholer in June 2015 and although his biography has been stripped from the Kaye Scholer website, according to a spokeswoman he remains a partner at the firm. The spokeswoman commented that Kaye Scholer is ‘conducting an internal investigation related to the allegations against [Mr Greebel] during his time at Katten,’ upon conclusion of which the firm ‘will take appropriate action.’ Source: Bloomberg BNA