The teenage suspect in the Boston Marathon bombings is in custody after being found hiding in a boat in a suburban homeowner's backyard.
Police said they exchanged gunfire with Dzhokhar Tsarnaev, 19, after cornering him in Watertown, near Boston.
He had escaped on foot early on Friday, apparently wounded, after a police shootout that claimed the life of his elder brother, an alleged accomplice.
Three people died and more than 170 were hurt in Monday's bombings.
At a Friday night press conference, US President Barack Obama promised to seek answers on what had motivated the bombers and whether they had help.
He spoke just after state police told journalists that the suspect was being treated at a Massachusetts hospital, bleeding and seriously injured with gunshot wounds to the neck and leg.
Also on Friday, investigators removed a computer and other evidence from the New Jersey home of the Tsarnaev brothers' sister, police said.
Ailina Tsarnaeva, who lives in the town of West New York, is said to have told FBI agents she had had no contact with her brothers for some time.