US Attorney Carmen M. ­Ortiz broke her silence late Wednesday night and defended her office’s actions against Aaron Swartz, the free information advocate who took his life last week while facing federal charges for hacking into MIT’s computer network. Ortiz, who charged the 26-year-old Swartz with offenses including wire and computer fraud, has faced a firestorm of criticism in the wake of Swartz’s hanging himself inside his Brooklyn, N.Y., apartment, on Friday.