"The Russian government expressed concerns that he [Tamerlan Tsarnaev] had become radicalized and that he might return to Russia and join extremist groups there," the bipartisan report, published Thursday, says.
The document, compiled by the House Committee on Homeland Security, reveals Russian intelligence services warned the FBI in 2011 about Tamerlan Tsarnaev, one of the two Chechen brothers accused of carrying out last year's Boston Marathon bombings.
The US scrapped a brief investigation into Tsarnaev after concluding he had no links to terrorism.
"The FBI did not find any evidence of terrorist activity, and this information was provided to the Russian government in the summer of 2011," the report states.
Russian intelligence agencies then sent a cable to the CIA, restating the warnings of the first memo. The next month, Tsarnaev was entered into the TECS system, a large database storing data on immigration and from other governments' lists of criminals and terrorists.
An alert was placed on Tsarnaev's name in case he popped up during international travel.
In 2012, American authorities intended to interview Tsarnaev upon arriving in the country after spending six months in Russia's Dagestan republic, suspecting he could have been trained as terrorist. But a misspelling of his name allowed him to avoid questioning.
The report provides detailed information on the terrorist networks in the Caucasus, as well as the history of the Tsarnaev family and a timeline of the events of the day of the bombing, including the manhunt for the brothers.
The report also prescribes measures for improving national security. First and foremost cooperation between federal and local law enforcement should be expanded, in addition to greater information sharing between various federal terror and travel watch lists.
"This report addresses procedures, personal actions, and a failure of information sharing that must be changed," said Rep. Bill Keating, a member of the committee that wrote the report.
Michael McCaul, the committee's chairman, stressed the importance of the report's recommendations saying they are "critical to fixing serious gaps in our counterterrorism efforts."
On April 15 last year two explosions at the finish line of the Boston Marathon killed three people and injured over 260.
The Tsarnaev brothers were quickly identified as suspects in the bombings following the release of surveillance camera footage by the FBI.
Tamerlan Tsarnaev was killed in a gunfight with police in the days following the bomb attack. His younger brother, Dzhokhar, tried to flee the city, but was wounded and later arrested and is now awaiting trial in federal court, scheduled to begin in November.
If convicted, he could face the death penalty.