the mother of now-dead bombing suspect Tamerlan Tsarnaev was recorded talking to someone in southern Russia who is under FBI investigation in an unrelated case, officials said.
The conversations are significant because, had they been revealed earlier, they might have been enough evidence for the FBI to initiate a more thorough investigation of the Tsarnaev family.
As it was, Russian authorities told the FBI only that they had concerns that Tamerlan and his mother were religious extremists. With no additional information, the FBI conducted a limited inquiry and closed the case in June 2011. Read: Iraq, Afghan wars had angered US bombers
Two years later, authorities say Tamerlan and his brother, Dzhohkar, detonated two homemade bombs near the finish line of the Boston Marathon, killing three and injuring more than 260. Tamerlan was killed in a police shootout and Dzhohkar is under arrest.
This photo shows (third from left) Tamerlan Tsarnaev, the first suspect and (second from left) Dzhokhar A. Tsarnaev, the second suspect, in the Boston Marathon bombings by law enforcement. AP
Also on Saturday, Federal Medical Center Devens spokesman John Collauti described the conditions under which 19-year-old Dzhokhar Tsarnaev was being held in the Ayer facility after being moved there from a hospital on Friday.
Dzhokhar was injured during a police chase on Thursday in which his brother, Tamerlan, was fatally wounded. Read: Boston bomb suspect kept in steel-doored small cell
Collauti said in a telephone interview that Dzhokar is in secure housing where authorities can monitor him. His cell has a solid steel door with an observation window and a slot for passing food and medication.
In the past week, Russian authorities turned over to the United States information it had on 26-year-old Tamerlan and his mother, Zubeidat Tsarnaeva. The Tsarnaevs are ethnic Chechens who emigrated from southern Russia to the Boston area over the past 11 years. Read: Boston bombing suspects' mom in terror database
The mother of the two Boston bombing suspects, Zubeidat Tsarnaeva, reacts at a news conference in Makhachkala, the southern Russian province of Dagestan. AP Photo
Even had the FBI received the information from the Russian wiretaps earlier, it's not clear that the government could have prevented the attack.
In early 2011, the Russian FSB internal security service intercepted a conversation between Tamerlan and his mother vaguely discussing jihad, according to US officials who spoke on condition of anonymity because they were not authorized to discuss the investigation with reporters.
The two discussed the possibility of Tamerlan going to Palestine, but he told his mother he didn't speak the language there, according to the officials, who reviewed the information Russia shared with the US.
In a second call, Zubeidat Tsarnaeva spoke with a man in the Caucasus region of Russia who was under FBI investigation. Jacqueline Maguire, a spokeswoman for the FBI's Washington Field Office, where that investigation was based, declined to comment.
There was no information in the conversation that suggested a plot inside the United States, officials said.
It was not immediately clear why Russian authorities didn't share more information at the time. It is not unusual for countries, including the US, to be cagey with foreign authorities about what intelligence is being collected.
Nobody was available to discuss the matter early Sunday at FSB offices in Moscow.
Jim Treacy, the FBI's legal attache in Moscow between 2007 and 2009, said the Russians long asked for US assistance regarding Chechen activity in the United States that might be related to terrorism.
"On any given day, you can get some very good cooperation," Treacy said. "The next you might find yourself totally shut out."
Zubeidat Tsarnaeva has denied that she or her sons were involved in terrorism. She has said she believed her sons have been framed by US authorities. Read: Boston suspects' mother slams US over son's death
The mother of the two Boston bombing suspects, Zubeidat Tsarnaeva, with the suspects' father Anzor Tsarnaev, left, speaks at a news conference in Makhachkala, the southern Russian province of Dagestan. AP Photo
But Ruslan Tsarni, an uncle of the Tsarnaev brothers and Zubeidat's former brother-in-law, said Saturday he believes the mother had a "big-time influence" as her older son increasingly embraced his Muslim faith and decided to quit boxing and school.
After receiving the narrow tip from Russia in March 2011, the FBI opened a preliminary investigation into Tamerlan and his mother. But the scope was extremely limited under the FBI's internal procedures.
After a few months, they found no evidence Tamerlan or his mother were involved in terrorism.
The FBI asked Russia for more information. After hearing nothing, it closed the case in June 2011. Timeline: What Tamerlan and Dzhokhar were doing between 2006-2013
In the fall of 2011, the FSB contacted the CIA with the same information. Again the FBI asked Russia for more details and never heard back.
At that time, however, the CIA asked that Tamerlan's and his mother's name be entered into a massive U.S. terrorism database.
The CIA declined to comment on Saturday. Read: Half of Americans anticipate more terrorist attacks, says poll
Authorities have said they've seen no connection between the brothers and a foreign terrorist group. Dzhohkar told FBI interrogators that he and his brother were angry over wars in Afghanistan and Iraq and the deaths of Muslim civilians there.
Family members have said Tamerlan was religiously apathetic until 2008 or 2009, when he met a conservative Muslim convert known only to the family as Misha. Misha, they said, steered Tamerlan toward a stricter version of Islam.
Two US officials say investigators believe they have identified Misha. While it was not clear whether the FBI had spoken to him, the officials said they have not found a connection between Misha and the Boston attack or terrorism in general.