NEW : A congressman says suspects ` ` likely '' the Boston attacks , then changed plans . NEW : Russia voiced concerns to the U.S. about the suspect , his mother , sources say . Dead Boston bomb suspect posted video of jihadist , analysis shows . Russia : Suspect told investigators he and his brother decided ` ` spontaneously '' to bomb NYC . Dzhokhar Tsarnaev , 19 , was ` ` more lucid '' the second time he was questioned , sources say .
NEW : A congressman says suspects ` ` likely '' the Boston attacks , then changed plans . NEW : Russia voiced concerns to the U.S. about the suspect , his mother , sources say . Russia : Suspect told investigators he and his brother decided ` ` spontaneously '' to bomb NYC . Dzhokhar Tsarnaev , 19 , was ` ` more lucid '' the second time he was questioned , sources say .