Dzhokhar Tsarnaev has publicly expressed remorse for the first time since he executed the 2013 Boston marathon bombings.
Security has been beefed up at the 2014 Boston Marathon, a year after the bombings that killed three people and injured hundred others.
A US grand jury has indicted accused Boston Marathon bomber Dzhohkhar Tsarnaev on charges of killing four people and using homemade bombs.
