BOSTON — The federal investigation into the Boston Marathon bombings has revised several significant details reported in the aftermath of the tragedy, especially the hunt for the perpetrators.
Investigators now say the surviving suspect, Dzhokhar Tsarnaev, 19, did not engage in a gun battle with the police SWAT team that captured him a week ago in a boat in suburban Watertown.
They said no weapon was found on him or in and around the boat even though officers riddled the small craft with bullets before pulling him out and handcuffing him.
At the time, police said they had "exchanged gunfire" with the suspect, and that they also feared he had explosives hiding in the boat. No explosives were found there.
Investigators did not say if any of the bullets fired at the boat struck Tsarnaev, who was bleeding from serious wounds and taken to a Boston hospital. They said he was at the scene of the gunfight between police and his older brother, Tamerlan Tsarnaev, 26, about 18 hours before the boat capture.
But they also disclosed that only one weapon, a 9mm handgun, was found at the earlier gunfight scene instead of the three guns that officials said at the time were recovered there. They said the gun was used by Tamerlan Tsarnaev to shoot at police, seriously wounding one officer and slightly injuring another.
Tamerlan died from bullet, shrapnel and other injuries sustained when his younger brother drove over his body while fleeing the gunfight in a stolen car. Investigators said the brothers had tossed a pressure cooker bomb like those used in the marathon explosions as well as handmade pipe bombs at police during the confrontation.
Investigators also contradicted reports that the younger brother's throat wound that has impeded his ability to speak resulted from an attempt to take his own life with a gun. They said it was caused by shrapnel from a makeshift bomb and not a bullet.
Additional information was released Wednesday about the killing of the campus police officer that touched off the nighttime gunfight and the daylong lockdown of the Boston area in search of the surviving suspect.
Investigators said they believe Sean Collier, 27, an MIT policeman, was ambushed while sitting in his cruiser on the Cambridge campus because the brothers wanted another gun. They said the pair fled without Collier's service revolver when they could not figure out how to release its triple-lock holster.
Collier's killing brought scores of officers into the area, and a motorist soon reported to police that his black Mercedes SUV had been carjacked by two men who said they were the marathon bombers and had killed a policeman.
Police were able to track the SUV from the driver's cellphone, which he left in the vehicle, setting off a police chase and high-drama events that eventually led to the death of Tamerlan Tsarnaev and the capture of Dzhokhar Tsarnaev.
Other developments in the bombing case:
-- Investigators said the two pressure cooker bombs that exploded near the marathon finish line were likely detonated by close-range remote controls like those used in kids toys.
-- Federal security officials in Washington were under fire for not sharing terrorist watch data on Tamerlan Tsarnaev in 2011 and 2012, when Russian authorities warned the FBI and CIA separately that he was a "strong believer" in radical Islam. House Speaker John Boehner said he wants to know "what agencies knew what, and the fact that it wasn't shared."
-- The mother of the Tsarnaev brothers told reporters in Russia that she will never accept that her sons planted bombs at the Boston Marathon. "America took my kids away from me," she said. She also said she regretted moving her family to the United States from the Dagestan region of Russia a decade ago. She and her husband later returned to Russia but the sons stayed in the Boston area. "Why did I ever go there? Why?" she said. "I thought America is going to, like, protect us, our kids. It's going to be safe."
-- Her surviving son's medical condition was upgraded by Beth Israel Deaconness Hospital officials in Boston from serious to fair. Investigators said he has remained silent since they informed him of his Miranda rights to refuse to answer questions and to have a court-appointed attorney. He is now represented by a lawyer.
-- No one has yet claimed the body of the older brother from the Boston morgue. But Anzor Tsarnaev, the father of the brothers, said he plans to arrive in the city soon to bury his oldest son and talk with the younger one. He said his wife is undecided about whether to accompany him because she is the subject of an arrest warrant on a shoplifting charge that she ignored when she returned to Russia.