The FBI did not initially share with Boston police the warnings from Russia’s security service in 2011 about one suspect in last month’s marathon bombings, despite the work of four city police representatives on a federal terrorism task force, Boston’s police commissioner told Congress on Thursday in the first public hearing on the attack.

Yet Commissioner Ed Davis acknowledged that police might not have uncovered or disrupted the plot even if they had fully investigated the family of Tamerlan Tsarnaev based on those warnings. After a cursory investigation the FBI closed its assessment on Tsarnaev, who died in a police shootout after the bombings. Boston police learned about the Russian warnings only later.

“That’s very hard to say. We would certainly look at the information, we would certainly talk to the individual,” Davis said. “From the information I’ve received, the FBI did that, and they closed the case out. I can’t say that I would have come to a different conclusion based upon the information that was known at that particular time.”

The congressional hearing was the first in a series to review the government’s initial response to the attacks, ask what information authorities received about Tsarnaev and his brother before the bombings and consider whether it was handled correctly.

Some lawmakers questioned whether Boston police could have more thoroughly investigated Tsarnaev after 2011, based on Russia’s vague warnings to the FBI and CIA or the discovery by the Homeland Security Department in 2012 that he was traveling to Russia for six months.

“Why didn’t they involve the local law enforcers who could have stayed on the case and picked up signals from some of the students who interacted with them, from the people in the mosque,” asked former Sen. Joe Lieberman, who also testified. “In this case, aggravatingly, you have two of our great homeland security agencies that didn’t involve before the event the local and state authorities that could have helped us prevent the attack.”

Davis’ testimony revealed a gap in information-sharing between federal and local officials. That was somewhat reminiscent of intelligence failures that preceded the 2001 terror attacks. Unlike those lapses, however, it’s not clear that anything would have been different, whatever coordination there might have been.

Led by the FBI, Joint Terrorism Task Forces operate in many cities as a way to bring federal, state and local officials together to share information. The model has existed for decades but, after 9/11, task forces sprouted up in cities nationwide to ensure that police were not out of the loop on investigations like the one the FBI conducted into Tsarnaev.

The hearing was conducted by the House Homeland Security Committee. The panel’s chairman, Rep. Michael McCall, R-Texas, and ranking Democrat, Rep. Bennie Thompson of Mississippi, both spoke of the importance of federal money, as did Lieberman.

“You can’t fight this war without resources,” Lieberman said.

In written testimony, Davis told lawmakers that cities should look at deploying more undercover officers and special police units and installing more surveillance cameras — but not at the expense of civil liberties.

“I do not endorse actions that move Boston and our nation into a police state mentality, with surveillance cameras attached to every light pole in the city,” Davis said. “We do not and cannot live in a protective enclosure because of the actions of extremists who seek to disrupt our way of life.”

Investigators used surveillance video from a restaurant near one of the explosions to help identify the Tsarnaev brothers.