The search for motive has included Tamerlan Tsarnaev’s increasing religious radicalization. In January, he angrily disrupted a sermon at the Islamic Society of Boston mosque in Cambridge, when a speaker praised Martin Luther King Jr., who was a Christian. Tamerlan was shouted out of the mosque after the outburst.
Later, a few volunteer leaders at the mosque sat Tamerlan down and warned him not to interrupt sermons or he would not be welcome, according to a statement Monday from the Islamic Society. He did not cause any more disturbances.
Russian authorities in 2011 warned the FBI that Tamerlan might be under the sway of Islamic radicals. The bureau investigated and found no evidence he was linked to terrorism. In 2012, Tamerlan spent six months in Russia.
A recent report by risk analysts at the forecasting firm IHS casts doubt on whether the Tsarnaev brothers had connections to terrorist groups such as the Caucasus Emirate in Russia. Such links “appear minimal,” the report states, in large part because the militant group is known to focus on local targets and has “little logical reason” to attack the United States.
“The more likely scenario is the brothers were self-radicalized individuals,” the report states. “The attacks [in Boston] were undertaken using very basic technology which requires minimal expertise and guidance that is easily accessible on the internet. This suggests that external training had not been provided.”
The report does not discount Tamerlan Tsarnaev’s visit to Russia, but says he probably only met people or witnessed events that “helped foster his radicalization.”
US Senator Lindsey Graham, a member of the Armed Services Committee, said Monday that the FBI had informed him it was initially unaware Tamerlan Tsarnaev had traveled to Russia due to a clerical error: His name was misspelled.
“He went over to Russia, but apparently, when he got on the Aeroflot plane, they misspelled his name,” Graham, a South Carolina Republican, said on Fox television. “So it never went into the system that he actually went to Russia.”
On Monday, President Obama called FBI Special Agent in Charge Richard Deslauriers, who led the bombing investigation, and Boston Police Commissioner Edward F. Davis to thank them “for their leadership and told them that the law enforcement officials, the citizens of Boston, and all affected by this tragedy were in his thoughts and prayers,” said the White House.
Beth Healy, Maria Sacchetti, Erin Ailworth, Bryan Marquard, Shelley Murphy, Eric Moskowitz, and Noah Bierman of the Globe staff contributed to this report. Mark Arsenault can be reached at Marsenault@globe.com.