Zubeidat told her: "It's real. My son knows all about it. You can read it on the Internet."
Kilzer said she only met Tamerlan once -- he wasn't friendly, she thought.
He was a dapper dresser and drove a Mercedes, according to an online photo gallery titled "Will Box for Passport."
"I'm dressed European style," Tamarlan said in a caption accompanying a photo of white leather shoes.
Photographer Johannes Hirn shot the images of Tamerlan at the Wai Kru Mixed Martial Arts Center on Brighton Street in Cambridge. That's where he trained before the Golden Gloves.
He was a good boxer, said Gene McCarthy from the Sommerville Boxing Club, who'd coached Tamerlan since he was 16.
He was tall -- over 6 feet -- with long arms and had determination written all over him. One time, he fought in a New England championship match even though he had the flu and fever blisters covered his lips. He won.
Tamerlan had been boxing since he was a kid -- his father began training him while they were still living in the Caucuses.
His younger brother started coming to the gym from the time he was 10, McCarthy said. Dzhokar followed Tamerlan around like a puppy. He'd be just behind him, doing calisthenics.
Tamerlan told Hirn, the photographer, that he gave up drinking alcohol and smoking in accordance with Muslim values. His aunt said he had become more devout a few years ago and started praying five times a day.
His mother told Russian TV channel RT that her oldest son embraced Islam but never spoke of anything extreme; never said he was on the side of jihad. Her son, she said, would never keep secrets from her. She would've known had he been involved in unsavory activities.
However, she said the FBI was checking on him, following his moves on the Internet.
"How could this happen? They were controlling every step of him, now they are saying this is a terrorist act," she said Friday.
FBI agents interviewed Tamerlan two years ago and also looked at his travel history, checked databases for derogatory information and searched for Web postings. But the agency found no connection with terror groups, an FBI official told CNN.
Tamerlan traveled to Sheremetyevo, Russia, in January 2012, according to travel records provided by a U.S. official. He returned six months later with a beard, those documents show.
A YouTube page in his name had links to Islamic websites, videos from a radical Australian preacher and rap music.
He had quit college, got married and had a daughter two years ago, said his aunt and father.
In an interview Friday with the Russian national TV network Zvezda in Dagestan, Anzor Tsarnaev said his sons had been framed. He said he had been trying to call Dzhokar but his phone is switched off. He'd spoken with Tamerlan the day before. He wanted to make sure Tamerlan was taking care of his brother; that he was studying hard.
This was Anzor's belief: that if his sons did not obtain an education, they would be left to toiling their entire lives.
But there were hints that perhaps all did not sit well for Tamerlan in his new country.