Investigators questioned Dzhokhar Tsarnaev for sixteen hours before he was read his Miranda rights, and he talked to them. But once he heard about his right to remain silent, he exercised it, the AP reports. Despite initially saying they would exercise a public safety exception and not read Tsarnaev his rights, and despite a group of senators saying he should be treated as an enemy combatant and not Mirandized at all, a judge and U.S. attorney came into his hospital room and read him his rights. And then he shut up.
While he was talking, Tsarnaev "told authorities that his older brother, Tamerlan Tsarnaev, 26, only recently had recruited him to be part of the attack, two U.S. officials said." But the fact that he did so before being advised of his rights means that everything he said before he was Mirandized might not be admissible in court. As the AP points out, however, that may be a moot point because "the FBI says Tsarnaev confessed to a witness," and there's plenty of physical evidence such as a 9mm handgun and that RC car remote control used to detonate the bomb. It's not like the suspects' flight from police was lightly documented.