Martin Shkreli, the boyish pharmaceutical entrepreneur who caused a public uproar after he drastically raised the price of a life-saving prescription drug, was arrested on Thursday for engaging in what U.S. prosecutors said was a Ponzi-like scheme at his former hedge fund and a pharmaceutical company he previously headed. Shkreli, who has become a lightning rod for growing outrage over soaring prescription drug prices, was arrested before dawn at the tony Murray Hill Tower Apartments in midtown Manhattan.