By Pam Benson
The name of one Boston Marathon bombing suspect was included in U.S. law enforcement and counterterrorism databases, but he was not on any watch list that would have prevented him from flying or required additional screening when he left or entered the country, according to intelligence and law enforcement officials.
After the FBI was asked by the Russians in early 2011 to investigate Tamerlan Tsarnaev's possible connection to jihadist causes, his name was put on a Customs and Border Prevention list known as TECS, used to detect unusual or suspicious travel, so that the FBI and other agencies would know if he traveled outside the United States.
The FBI investigation turned up no terrorism threat or any other derogatory information and the case was closed in June of 2011.
Several months later in the fall of 2011, the CIA received from the Russians information almost identical to what had been given to the FBI, according to a U.S. intelligence official.
The Russian information included a name variant and two possible dates of birth.
At the request of the CIA, that information about Tsarnaev was included in the Terrorist Identities Datamart Environment list, otherwise known as TIDE, which is maintained by the National Counterterrorism Center, CNN has learned.
The list of more than 500,000 names of known or suspected foreign and domestic terrorists contains detailed, raw intelligence.
At about the same time, Tsarnaev's name was also added to the FBI's Terrorist Screening Database (TSDB), a list which is similar to TIDE but without the detailed intelligence information.
The two lists are linked. New intelligence and data are developed and added to TIDE multiple times a day. When that happens, the TSDB database also is updated.
Both files are tools for law enforcement and intelligence agencies to share information on terrorism suspects.
About 98 percent of the names on the two lists are foreign citizens, according to officials.
From the lists, the FBI Terrorism Screening Center recommends which names should be put on watch lists used by the Transportation Security Administration, the State Department and the FBI.
These include "no-fly" and other lists which would require additional screening.
Tsarnaev's name was not added to any of those lists, according to officials.
A federal law enforcement official said the "U.S. never deemed him a threat."
But his name was on the customs TECS list to look out for any travel by him during a one year period which started at the time the FBI was investigating him in 2011.
When Tsarnaev, 26, traveled to Russia in January of 2012, the FBI was notified of his departure.
By the time he returned the following July, the notification period had expired and therefore the FBI was not "pinged," according to the intelligence official.
Tamerlan Tsarnaev died last week following a shootout with police. The other bombing suspect, his brother Dzhokhar, 19, was captured.
CNN's Carol Cratty contributed to this story.