Just over a month after Boston Marathon bombing suspect Tamerlan Tsarnaev was killed during a standoff with police, investigators said they have begun to piece together a picture of what he did during a six-month visit last year to Dagestan, a volatile region in southern Russia that is home to Tsarneav's parents as well as a violent struggle with Islamist insurgency.
American investigators believe Tsarnaev traveled to Dagestan seeking to make contact with militant groups, but for reasons that remain unclear, he was either unable or unwilling to join their ranks.
As they peel back the layers of the man accused of working with his younger brother to set off a pair of bombs near the finish line of the Boston Marathon April 15, investigators said they are finding a frustrated young man who felt out of place in the United States.
They said Tsarnaev appears to have been largely self-radicalized before arriving in Dagestan in search of a lifestyle that may not have met his expectations either, according to U.S. officials close to or briefed on the investigation. The officials spoke on the condition of anonymity.
The officials described Tsarnaev as a typical lone wolf.
While Tsarnaev's radicalization appears to have deepened during his time in Dagestan, investigators have not found a particular contact there or a "manifesto," on his computer or elsewhere that would explain why he and his younger brother Dzhokhar allegedly placed bombs at the finish line of the Boston Marathon, the officials said. Hours after Tamerlan was killed in the police shootout, Dzhokhar was apprehended and remains in custody.
While officials stressed the investigation is still ongoing, they have also found no signs that Tamerlan Tsarnaev was affiliated with an international terror organization like al Qaeda. Similarly, they have found no evidence to suggest he was directed to strike the U.S. by anyone he met in Dagestan. They have not found any signs of suspicious contacts during Tsarnaev's trips to visit his father's family in Chechnya, which has also battled an Islamist insurgency, and probes into Tsarnaev's father's rumored ties to Chechen security officials have also not revealed anything of concern, the officials said.
Tamerlan Associate Joined Militant in 'The Forest', But Not Tamerlan
Tsarnev's closest known militant contact in Dagestan appears to have been a young man named Mahmud Mansur Nidal, officials said. The two were often seen together leaving a Salafist mosque, popular with fighters, in Makhachkala.
But while Nidal eventually went off to join a militant group -- what locals call going "into the forest" -- investigators say they have uncovered no evidence that Tsarnaev joined him. Nidal would eventually be killed in a police raid after returning to visit family.
Tsarnaev had also been in touch over the internet with a Russian-Canadian convert to Islam and suspected militant named William Plotnikov, but officials say they have no evidence to suggest the two ever met in person. Contrary to previous reporting, investigators say they do not believe Tsarnaev dropped off the map after Plotnikov was killed by police in July, shortly before Tsarnaev left Russia to return to the United States.
Investigators have also taken a hard look at Magomed Kartashov, Tsarnaev's distant cousin and the founder and leader of a Islamist group called the Union of the Just. The group is anti-American and campaigns for the application of Sharia, or Islamic law.