The FBI had "stonewalled us completely," Rep. Peter T. King, New York Republican, said during an open hearing of the House Committee on Homeland Security, adding that it is "totally unacceptable" that the bureau is failing to cooperate.
"Part of our oversight has to be that case-closed procedure," said Rep. William R. Keating, Massachusetts Democrat. "Something's wrong."
Rep. Michael T. McCaul, Texas Republican and committee chairman, said the panel would hear testimony Thursday from homeland security and counterterrorism officials in closed session.
Witnesses and lawmakers said Massachusetts authorities might have foiled the bombing if local police had followed up on Russian suspicions about Tamerlan Tsarnaev, one of the two Chechen-American brothers accused in the bombing. But the FBI never shared the tip from Moscow with state and local authorities.
"I don't know why they didn't go to the local police," former New York Mayor Rudolph W. Giuliani said. "I believe there was an obligation to notify [state and local police]. ... I don't know if this is an individual thing that went wrong or a systemic thing."
Mr. Giuliani said the FBI had not informed local police on the Boston-based Joint Terrorism Task Force about Russia's warning.
"As a matter of help, you would go to the Boston police and say, 'What do you know about him?'" he said of the FBI.
In 2011, the elder of the two brothers, Tamerlan Tsarnaev, his relatives and friends were interviewed by the FBI after Russian authorities had warned he might be radicalizing and preparing to come to Russia to join Islamic extremist groups in the Muslim-majority North Caucasus.
In 2012, Tsarnaev traveled to Russia, but the FBI had closed the file on him after finding no evidence of terrorist activity.
Upon his return, he began posting extremist videos on his YouTube account. He also began planning to bomb a large public event, according to the indictment against his younger brother, Dzhokhar. The elder brother was killed in a shootout with police a few days after the April 15 bombing, which killed three people and injured more than 250.
Mr. Giuliani said the nature of al Qaeda's terrorism is shifting from large, complex global plots, and evolving into a threat from so-called "lone wolves" — extremists who stage attacks without the assistance of a network.
"If the threat is from lone wolves ... isolated, single individuals [and] small groups ... the FBI isn't going to find them, you're only going to find them with the local police," he said.
Mr. Giuliani repeatedly suggested that Boston police could have put the brothers, who lived in Cambridge, Mass., under surveillance. Local police could have followed the Tsarnaevs, questioned people at their mosque and gathered information about them, he said.
That view brought a word of caution from one of Mr. Giuliani's fellow witnesses, former National Counterterrorism Center Director Michael Leiter.
"There are real civil liberties issues here," Mr. Leiter said, noting that FBI cases generally are closed for good reasons. He asked if "we're going to start getting local police to put ... surveillance on" everyone who has been cleared by the FBI.
"Think of that in the domestic terrorism context," he said, citing as an example "a guy who's got a lot of guns" whose neighbors report him to FBI, who interview him and find he "just likes to shoot guns."
"How long do you keep going back?" he said.
Mr. Giuliani argued that the occasional overreach is worthwhile.
"Do we want to err on the side of never making a mistake and possibly wrongly identifying someone as a terrorist, or do we want to err on the side of not having more bombings like Boston?" he said.
In Boston on Wednesday, Dzhokhar Tsarnaev, 19, pleaded not guilty to 30 federal charges, including using a weapon of mass destruction to kill, during a seven-minute court hearing — his first public appearance since being captured four days after the bombings.
He appeared in the heavily guarded, packed courtroom with his arm in a cast and his face swollen, with swelling around his left eye and cheek. After giving his plea to the 30 charges, he was led out of the courtroom in handcuffs, making a kissing gesture toward his family with his lips.
He could be eligible for the death penalty if prosecutors choose to pursue it.
This article is based in part on wire service reports.