The New York Times reports on the arsenal of guns and explosives amassed by terror suspects Tamerlan and Dzhokhar Tsarnaev; they were apparently planning more murderous attacks.

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 are 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.”