William Farrington / Polaris The American wife of suspected marathon bomber Tamerlan Tsarnaev, Katherine Russell, leaving the house where he lived on Norfolk Street in Cambridge, Mass.

The American wife of the dead Boston Marathon bombing suspect is cooperating with investigators, and her husband’s alleged involvement in the attack came as an “absolute shock,” her lawyers said Tuesday.

The lawyers would not say whether Katherine Russell, who is known as Katie and married Tamerlan Tsarnaev in 2010, had already spoken with the FBI.

"The reports of involvement by her husband and brother-in-law came as an absolute shock to them all," lawyer Miriam Weizzenbaum said, speaking of Russell’s family, according to NBC affiliate WJAR in Providence, R.I.

"As a mother, sister, daughter, wife, Katie deeply mourns the pain and loss to innocent victims," she added.

Another lawyer, Amato DeLuca, said that Russell was doing "everything she can to assist with the investigation."

Russell converted to Islam after she met her future husband at a nightclub in 2009. She dropped out of college, got married and had a baby three years ago. She has been living in Cambridge, Mass., raising the child and working as a home health aide, the lawyers said. She has also been spending time with family in Rhode Island.

Tamerlan Tsarnaev, 26, was killed after a shootout with police early Friday. His brother, Dzhokhar, 19, was captured that night, hiding in a boat in a suburban Boston driveway, after a daylong manhunt that paralyzed the Boston area.

Dzhokhar Tsarnaev has been charged with conspiring to use a weapon of mass destruction and could face the death penalty. He was upgraded to fair condition from serious Tuesday at a Boston hospital.

The mother of the two brothers suspected of the Boston Marathon bombing has told ITV News that her sons went to the event last year. Her chilling admission comes a day after her youngest son was charged with the crime in hospital. From her home town in Dagestan, ITV's Martin Geissler reports.

Authorities said the brothers led police on a wild chase that began late Thursday. They shot and killed a college patrol officer, carjacked an SUV and engaged police in a wild, 200-shot gun battle, tossing explosives out the window of a car, authorities said.

The FBI checked out Tamerlan Tsarnaev in 2011, after the Russian government raised concerns that he might have ties to extremist groups, but turned up nothing, law enforcement officials have said.

Meanwhile, The brothers' mother, Zubeidat Tsarnaeva, told the British broadcaster ITN on Tuesday that she was aware that investigators had talked to Tamerlan in the past, and that investigators had also spoken with her.

She said she was asked, "'He’s like a leader, he’s a strong boy, and do you think that he could get involved into kind of like any organization, you know like radical organization?' At that time because they told me that they saw whatever he was reading. And I said no, no."

"What happened was a terrible thing,” the mother told ITN from Makhachkala, in southern Russia. “But I know that my kids have nothing to do with this. I know it. I am mother. I know my kids. I know my kids."

And also late Tuesday, the suspects' sisters, Ailina and Bella Tsarnaev, who live in New Jersey, released a short statement through their lawyers, which read: "Our heart goes out the victims of last week’s bombing. It saddens us to see so many innocent people hurt after such a callous act. As a family, we are absolutely devastated by the sense of loss and sorrow this has caused. We don’t have any answers but we look forward to a thorough investigation and hope to learn more."

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