New Details Emerge About The Tsarnaev Brothers' Time In The United States

BOSTON (CBS) - While it is clear the older brother's personality took an ugly turn in recent years. it is not clear why his younger brother followed him down that path.

Luis Vasquez of Cambridge says he was a friend of Tamerlan, the older brother. But actually knew both of them. He taught wrestling to his younger brother.

"He needs to cooperate. We need answers," Vasquez said.

Standing a few feet from the bombing sites on Boylston street, Vasquez was sharing his story with national media outlets saying he knew Tamerlan traveled to Russia last year but thought nothing of it.

"Maybe it is a blessing in disguise that he was eliminated. We have little brother, it is a little weaker. He was not the brain behind this I don't feel," he said.

Not far from Boylston Street, there was extra security outside the Islamic Society of Boston in Cambridge .

Tonight we know older brother Tamerlan was an occasional visitor. And we also know he disrupted a holiday sermon back in January as the speaker was praising Martin Luther King.

Anwar Kazmi remembered it this way.

"You know how Martin Luther King has inspired people, just like our Prophet Muhammad has inspired people? He was somehow offended by that he stood up and objected to it," Kazmi said.

Tamerlan Tsarnaev's wife, Katherine has also been questioned by federal authorities. She was led out her home in Cambridge, Friday by the FBI. She claims she knows nothing.

Documents obtained by WBZ show she was beaten up by her husband in July 2009.

Tamerlan was arrested after he admitted to Cambridge police that he had slapped her.

We also know that the mother of the two men lived at the same Norfolk Street address in Cambridge.

Zubeibat Tsarnaev is a licensed cosmetologist in the state of Massachusetts. she apparently worked from the home address.

We also know the mother of the two men was arrested in 2012 for shoplifting from Lord and Taylor in Natick.

Police say she was caught stealing $1,600 worth of dresses and ruined another $300 worth of dresses by cutting the security tags off them.

She recently forfeited her bail when she failed to show up in court.