Boston and Massachusetts law enforcement officials confirmed Thursday that federal agents left them in the dark on the growing warning signs about Tamerlan Tsarnaev in the run-up to the Boston Marathon bombing.

Boston Police Commissioner Edward Davis, in testimony on Capitol Hill, said his officers on a joint terrorism task force were never told about an explicit warning from the Russian government or about Tsarnaev's travel to the Chechnya region last year. Davis said he would have liked to have known about that activity, and that it "absolutely" would have merited a second look at Tsarnaev.

Davis and Massachusetts homeland security official Kurt Schwartz testified that their officers were not looped in on Tsarnaev until after the bombing.

"At no time prior to the bombings did any member of the Massachusetts State Police or the fusion center have any information or knowledge about the Tsarnaev brothers," Schwartz said.

Current and former lawmakers at the committee hearing Thursday expressed disbelief at the lack of information-sharing.

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"The idea that the feds have this information and it's not shared with the state and locals defies why we create the Department of Homeland Security in the first place," said Rep. Michael McCaul, R-Texas, chairman of the House Homeland Security Committee.

Former Sen. Joseph Lieberman, a witness at Thursday's hearing, called the failure to tell Boston police about the brothers "a serious and aggravating omission."

"This may be one of the most significant and painful takeaway lessons," he said.

Officials continue to question what warning signs were missed about the Tsarnaev brothers. Attention has been drawn to a 2011 warning from the Russian government to the FBI about Tamerlan Tsarnaev. The FBI has revealed it was told Tsarnaev was a "follower of radical Islam" and was preparing to travel overseas. The FBI says it interviewed Tsarnaev and found no evidence of terrorist involvement.

Tsarnaev ended up traveling to Russia for six months in early 2012.

Even in the federal government, information may not have traveled across all relevant agencies. Homeland Security Secretary Janet Napolitano has said the government's internal system "pinged" when Tsarnaev left the country in 2012, though a Republican senator has said the FBI claimed they were not aware of that trip.

Davis said Thursday his department was not told of any of those developments, and repeatedly said he would have liked to know.

"We were not aware of Tamerlan's activities," he said. Davis said he can't say he would have reached a different conclusion than the FBI, but the developments would have prompted another look.