The Boston bombing suspect who is still on the run became a US citizen on September 11 last year, according to documents obtained by NBC News.
Dzhokhar Tsarnaev, 19, had a Massachusetts driver’s license and was living in Cambridge, near Boston.
Detectives in Boston are looking further afield as they piece together their case against Marathon suspect Dzohkhar Tsarnaev.
The uncle of Boston bombing suspect Tamerlan Tsarnaev described his recent visit to Dagestan in Russia and his great shock at the attacks.
Both men were enrolled in a school in Dagestan, a neighbouring region that was drawn into Chechnya's violence during the 1990s.