Suspects seemed set for attacks beyond Boston

WASHINGTON: The two men suspected in the Boston Marathon bombings were armed with a small arsenal of guns, ammunition and explosives when they first confronted the police early Friday, and were most likely planning more attacks, the authorities said Sunday.

United States officials said they were increasingly certain that the two suspects had acted on their own, but were looking for any hints that someone had trained or inspired them. The F.B.I. is broadening its global investigation in search of a motive and pressing the Russian government for more details about a Russian request to the F.B.I. in 2011 about one of the suspects’ possible links to extremist groups, a senior United States official said Sunday.

New details about the suspects, their alleged plot and the widening inquiry emerged on Sunday, including the types of weapons that were used and the bomb design’s link to a terrorist manual. Lawmakers also accused the F.B.I. of an intelligence failure, questioning whether the bureau had responded forcefully enough to Russia’s warnings.

The surviving suspect, Dzhokhar Tsarnaev, 19, remained in a Boston hospital in serious condition. The authorities said they believed that he had tried to kill himself, because a gunshot wound to his neck “had the appearance of a close-range, self-inflicted style,” the senior United States official said.

As investigators intensified their search for clues, the investigation’s focus shifted in the last two days from a manhunt that relied heavily on cutting-edge surveillance technology to help track down the suspects to more traditional investigative methods. Those approaches include interviews with friends, relatives and others who knew the suspects and examinations of computers, phones, writings and their possessions.

More details of what the authorities said the original plot were becoming clearer. The Boston police commissioner, Edward Davis, said the authorities believed that Mr. Tsarnaev and his older brother, Tamerlan, 26, had planned more attacks beyond the bombings at the finish line of the Boston Marathon, which killed three people and wounded more than 170. When the suspects seized a Mercedes-Benz sport utility vehicle and held the driver hostage, they told him that they planned to head to New York, the senior United States official said Sunday.

It was not clear whether the suspects had told the driver what they planned to do there.

Mr. Davis told CBS News’s “Face the Nation” on Sunday: “We have reason to believe, based upon the evidence that was found at that scene — the explosions, the explosive ordnance that was unexploded and the firepower that they had — that they were going to attack other individuals.”

Along with determining that the suspects had made at least five pipe bombs, the authorities recovered four firearms that they believe the suspects used, according to a law enforcement official. The authorities found an M-4 carbine rifle — a weapon similar to ones used by American forces in Afghanistan — on the boat where the younger suspect was found Friday night in Watertown, Mass., 10 miles west of Boston.

Two handguns and a BB gun that the authorities believe the brothers used in an earlier shootout with officers in Watertown were also recovered, said one official briefed on the investigation. The authorities said they believe the suspects had fired roughly 80 rounds in that shootout, in which Tamerlan Tsarnaev was fatally wounded, the official said.

Among the unanswered questions facing investigators where the suspects acquired their weapons and explosives, how they got the money to pay for them, and whether others helped plan and carry out the attack last Monday. Mayor Thomas M. Menino of Boston said he believed the brothers were not affiliated with a larger network. “All of the information that I have, they acted alone, these two individuals, the brothers,” he said on ABC News’s “This Week.”