The name of the mother of alleged Boston bomber Tamerlan Tsarnaev was placed in a U.S. terrorism database at the same time as her son's was in October 2011.

The CIA requested that both their names be placed in the U.S. government's terrorism database known as TIDE (Terrorist Identities Datamart Environment) after it received information from the Russian government that it considered the pair to be potential Islamic militants. An earlier FBI investigation prompted by another Russian request determined that Tamerlan Tsarnaev had no ties to terrorism.

(Image Credit: Musa Sadulayev/AP Photo)

Tsarnaev died in a fierce gun fight with Boston police last week. He and his younger brother, Dzhokhar, are accused of carrying out the bombings at the Boston Marathon that killed three and injured more than 260. Dzokhar Tsarnaev, 19, is in the Federal Medical Center Devens, about 40 miles from Boston.

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On Thursday, at a news conference in Makhachkala, Russia, Zubeidat Tsarnaev said her sons had been "framed" by U.S. authorities, and she denied that her son had made contacts with Islamist militants during an extended visit to Russia last year.

Inclusion on the TIDE list of 700,000 names does not mean an individuals are suspected of carrying out terrorist activities or that they require surveillance or face travel restrictions. Instead, the list, maintained by the National Counterterrorism Center, serves as the base point for relevant federal agencies to come up with more specific watch lists that match their criteria, such as the Transportation Security Administration's no-fly list.

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Earlier in the week U.S. officials confirmed that Russia's intelligence agency, the FSB, had made two separate requests of the FBI and the CIA to investigate Tamerlan Tsarnaev for potential ties to Islamic extremists. The FBI's investigation in early 2011 concluded that Tsarnaev did not have ties to terror groups. That information was conveyed to the FSB, but the FBI never received a response.

The intelligence official says that a subsequent FSB request sent to the CIA in September 2011 to investigate Tamerlan Tsarnaev also contained information about his mother, Zubeidat Tsarnaeva.

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The official said the Russian request indicated the pair were considered to be strong believers in Islam and potential militants, and it was feared they might cause trouble if they came back to Russia.

A U.S. official said earlier this week that the CIA had "nominated" Tamarlan Tsarnaev's name for inclusion in the TIDE database out of "an abundance of caution." It was later determined that the alternate spelling of his names and dates of birth provided by Russia to the CIA were all incorrect.

Tamerlan Tsarnaev was also included in a separate database in the spring of 2011 as the FBI tried to determine whether he had conducted any foreign travel.

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Those entries place in TECS - the Treasury Enforcement and Communication System - remain active for only a year.

This was the database that Homeland Security Secretary Janet Napolitano told a Senate panel Tuesday had "pinged" when Tsarnaev left the United States in January 2012 on a six-month trip to Russia. The trip has been a focus of speculation that Tsarnaev might have made contact with or received terrorist training in the Dagestan region where he was visiting relatives.

A U.S. official explained that the positive hit when Tsarnaev left the United States resulted in the Joint Terrorism Task Force's being notified that he had left the country. It is unclear which federal agency within the task force would have actually received the notification of his travel and what was done with the information.

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When Tsarnaev returned to the United States in June 2012, there was no "ping" of his TECS database entry because it had already expired. TIDE entries do not expire, but there was also no positive hit in the TIDE database because it turned out that all of the personal details provided to the CIA by Russia were inaccurate.

According to the official, even if Tsarnaev's name and details had been accurately fed into the TIDES database, U.S. customs officials would have found that the FBI's investigation had been closed and that it had not been determined that he was a threat.

Furthermore, even if the TECS database entry for Tsarnaev had not expired after a year, that, too, would have brought up the information that his case had been closed.