It was reported by a U.S. Official yesterday that the elder of the two brothers suspected of the Boston Marathon bombings, Tamerlan Tsarnaev, was on the counter-terrorism watch-list.

It was last night that Vice-chairman of the Senate Intelligence committee revealed to the public that in 2011, Tsarnaev was placed on the list after the Russian government warned the U.S., not just once but twice, that that country suspected that Tamerlan had become radicalized and should be considered a threat.

After the second warning, Tamerlan’s identity and information was shared with the FBI, Homeland Secuurity and the State Department. When interviewed by the FBI, the FBI did not detect anything untoward about Tamerlan and the case was not pursued. But even so, Tamerlan’s name was added to the Terrorist Identities Datamart Environment list.

Officials say that the reason why tabs were not kept on Tamerlan was because the TIDE list was too long. The counter-terrorism list is populated with 540,000 names.

Even though Tamerlan’s name was on the TIDE list, his name was never added to the “No Fly” List or the Selectee list which would have required the man to be subject to additional screening at airports.

Tsarnaev’s name had also been added to the Homeland Security Department’s list at the Customs and Border Protection Bureau, but that raised no flags as well when Tamerlan returned back from Russia in 2012. No alerts were triggered when he re-entered the U.S. After that visit because the investigation into his activities had ended.

Janet Napolitano, the Homeland Security Secretary told the Senate Judiciary Committee on Tuesday, “Yes, the system pinged when he was leaving the United States. By the time he returned, all investigations in the matter had been closed.”

It is reported that Tamerlan was killed in a shootout with police on Friday. Other reports say that Tamerlan was killed when his younger brother, Dzhokhar Tsarnaev, ran over him with the stolen vehicle that they were in, when they led authorities on a wild chase that included gunfire and bombs being tossed out of the vehicle at police.

The younger Tsarnaev was captured the next day when an alert homeowner discovered Dzhokhar, in the man’s boat which was stored in his backyard, just outside the perimeter that authorities had set up in an attempt to capture the bombing suspect.

The brothers are suspected of being responsible for the two bombs made from pressure cookers that detonated near the finish line of Boston’s annual Marathon, killing three and wounding more than 260 others.