Investigators believe Tamerlan Tsarnaev and his younger brother, Dzhokhar, likely made the bombs they are suspected of setting off at last month's Boston Marathon in Tamerlan's home in Cambridge, Massachusetts, law enforcement officials said on Friday.
FBI agents have been questioning Tamerlan's wife, Katherine Russell, and other witnesses for days to try to piece together exactly how and where the devices were made and what people knew about the brothers' beliefs and plans. Investigators said they are increasingly convinced that the ethnic Chechen brothers lifted their bomb designs from Internet postings by Islamic militants, though they substituted some components, and made the lethal devices less than five miles (8 km) from the spot where the bombs killed three and injured 264.
Tamerlan Tsarnaev, 26, and his 24-year-old wife lived on Norfolk Street in Cambridge. Tamerlan spent hours alone there, minding the couple's young child as his wife worked up to 80 hours a week as a health aide, her lawyer, Amato DeLuca, has said. His brother Dzhokhar, 19, was enrolled as a student at the University of Massachusetts and lived in a dormitory on the school's Dartmouth campus, about an hour's drive from Boston. Investigators believe that during his long days at home alone, Tamerlan, who enjoyed expensive clothes and cars and occasionally worked as a mechanic, likely honed his bomb-making skills with materials found around the house. Police had said the bombs were built from pressure cookers packed with nails and ball bearings.