Lawyers for Retrophin and Shkreli, whose arrest was witnessed by Reuters, did not immediately respond to a request for comment. Turing and KaloBios declined to comment.
Turing sparked controversy earlier this year after news reports that it had raised the price of Daraprim, a 62-year-old treatment for a dangerous parasitic infection, to $750 a tablet from $13.50 after acquiring it.
Shkreli, 32, was expected to be charged on Thursday for illegally using Retrophin assets to pay off debts after MSMB lost millions of dollars, the source said.