The man, whose real name is Mikhail Allakhverdov, denies ever encouraging a violent take on Islam and says he was not Tamerlan's teacher, according to a New York Review of Books writer who says he interviewed Misha.
"He began telling me he cooperated with the FBI" and had handed over his computer and cell phone, reporter Christian Caryl told CNN on Monday.
Allakhverdov insisted he had "nothing to do with radicalization," Caryl said.
CNN has made repeated efforts to speak with Allakhverdov, but has so far been unsuccessful.
A lawyer who stepped out of the West Warwick, Rhode Island, apartment listed for Mikhail Allakhverdov told CNN he represents the parents of someone who lives there, adding, "We call him Michael."
The parents have answered all questions the authorities have asked of them, attorney Richard Nicholson said.
The parents are nervous because of the media focus on them, he said, adding that the mother has a heart condition.
Misha's family 'friendly and welcoming'
Caryl said that when he showed up at Misha's home, he took the family by surprise but managed to spend some time with him.
"I wasn't his teacher. If I had been his teacher, I would have made sure he never did anything like this," Allakhverdov said, according to Caryl's report.
"A thirty-nine-year-old man of Armenian-Ukrainian descent, Allakhverdov is of medium height and has a thin, reddish-blond beard," Caryl wrote. "When I arrived he was wearing a green and white short-sleeve football jersey and pajama pants. Along with his parents, his American girlfriend was there, and we sat together in a tiny living room that abuts the family kitchen."
He added, "In many ways, Allakhverdov's parents seem typical former-Soviet émigrés who had embraced middle class life in the United States. His father is an Armenian Christian and his mother is an ethnic Ukrainian."
In the article, Allakhverdov's father is quoted as saying, "We love this country. We never expected anything like this to happen to us."
Ruslan Tsarni, Tsarnaev's uncle, told CNN last week that a friend of his nephew "just took his brain. He just brainwashed him completely."
After The Associated Press said members of Tsarnaev's family identified the friend as Misha, Tsarnaev's former brother-in-law told CNN that Tsarnaev had a friend by that name. Elmirza Khozhgov said the friend apparently "had influence on Tamerlan." But Khozhgov said he did not see Misha try to radicalize Tsarnaev.
Death-penalty expert to defend bomb suspect
Tsarnaev, 26, died after a shootout with police. His younger brother, Dzhokhar, 19, sustained gunshot wounds and is being held at a prison medical facility west of Boston. He has been charged with using and conspiring to use a weapon of mass destruction resulting in death, as well as one count of malicious destruction of property by means of an explosive device resulting in death.
On Monday, a federal judge appointed prominent defense lawyer Judy Clarke to represent the wounded suspect, who could be sentenced to death if convicted.
Legal colleagues consider Clarke to be the nation's foremost expert on defending federal capital cases. She has represented numerous high-profile clients facing Death Row, including Ted Kaczynski, the Unabomber; Eric Rudolph, who admitted to the 1996 Atlanta Olympic bombing and other attacks; and Jared Lee Loughner, who pleaded guilty to killing six people and wounding 13, including then-U.S. Rep. Gabrielle Giffords, in a Tucson, Arizona, shooting spree. All of them are serving life in prison.
Landfill search turns up empty