Providence - Before Tamerlan Tsarnaev died in a shootout with police, he was a husband and father. Katherine Russell Tsarnaev, an artist, dancer and college drop-out from suburban Rhode Island converted to Islam to marry him and bear his child.

Investigators want to know what she knows.

Since the Boston Marathon bombing April 15, Katherine Tsarnaev, 24, left the Cambridge, Mass., apartment where she lived with Tamerlan and has been staying with her parents in their corner-lot, two-story beige home in wooded North Kingstown, R.I. FBI agents entered the house Monday, part of the effort to piece together details of the accused terrorist's life.

Investigators have told U.S. lawmakers that Tamerlan, 26, and his brother, Dzhokhar, 19, learned radical Islam and bomb-making online. The Russell family's lawyer, Amato DeLuca, said last week that Katherine had no foreknowledge of the attacks.

"No indication, no inkling, no inclination, no hint, no nothing," DeLuca said in an interview. "She was as shocked as anybody, believe me."

Still, questions abound about what those closest to the suspects did or didn't know. Authorities are examining whether the suspects had help, though there's no evidence so far that they did, according to a U.S. official who asked not to be identified because of the continuing investigation.

Investigators found female DNA on a fragment from one of the bombs, another U.S. official briefed on the probe said Monday. The genetic material may have come from a number of sources and its discovery doesn't necessarily mean that additional people were involved, said the official, who asked not to be identified in discussing an open case.

DeLuca said in an email Monday that "Katie continues to assist in the investigation in any way that she can," without elaborating.

The FBI took DNA samples from Tsarnaev Monday, according to one of the U.S. officials briefed on the probe. Jason Pack, an FBI spokesman, declined to say whether the agency may seek a subpoena to interview Katherine or whether she's cooperating voluntarily.

"We aren't permitted to discuss specific aspects of our case," he said.

Since the bombing, Tsarnaev has rarely left the home in North Kingstown, which is 70 miles south of Boston. On her few excursions, she emerged in long black skirts and a hijab head covering, ducking photographers.

She hasn't granted public interviews. Her family has issued statements only through their lawyer, expressing condolences for the bombing victims - three dead and more than 260 wounded - and Katherine Tsarnaev's sadness at Tamerlan's death.

A swarm of media cars and trucks has been stationed outside the home for days, along with official-looking black sedans and police cars.

The troubled ethnic Chechen immigrant family into which Tsarnaev married at 21 bore little resemblance to her own. Her existence went from a childhood in a leafy suburb to one in which she shared a cramped apartment in Cambridge with Tamerlan, their daughter, and Tamerlan's parents until their return to Russia.

Katherine "Katie" Russell Tsarnaev was born in Texas on Feb. 6, 1989, according to her marriage certificate dated June 21, 2010. She's the eldest of three daughters of Warren Russell, an emergency medicine physician, and Judith, a registered nurse.

On Coriander Lane in North Kingstown, neighbor Dave Mather, a 44-year-old biology teacher, recalled all the Russell girls as polite. They played together on the lawn of their corner property, often while the parents gardened.

In the past few years, Tsarnaev had adopted conservative religious dress, Mather said as he trimmed his grass last week. She visited her parents often, waving and smiling whenever she spotted neighbors from the cul-de-sac.

At North Kingstown High School, Tsarnaev excelled in drawing, according to Amos Trout Paine, 42, an art teacher who left the district in 2010. Paine said he hadn't been in contact with her since graduation.

In 12th grade, Tsarnaev enrolled in independent studies to work on a portfolio for college applications, Paine said. Sometimes she talked about a career in graphic design.

"She had a good amount of talent," Paine said by phone from his home in Providence last week. Socially, he described her as "part of the whole crew," not sticking to a particular group.

Tsarnaev graduated from North Kingstown High School in 2007 and landed in trouble that summer. Warwick police arrested her on July 26 on a misdemeanor shoplifting charge. The case was dismissed Aug. 20, according to records maintained by Rhode Island's Third District Court in Kent County.

The arrest was out of character for a "great student," Paine said.

Her character changed still more dramatically after high school.

Tsarnaev went to Suffolk University in Boston to study communications, and she met Tamerlan, a former boxer who in 2009 had been charged with assaulting a live-in girlfriend.

National Public Radio interviewed three college roommates of Katherine Tsarnaev who described Tamerlan as controlling, manipulative and angry. The women, whom NPR didn't name, said he called her names like "slut" and "prostitute" and demanded that she convert to Islam, NPR said.

Tsarnaev married Tamerlan at a mosque in the Dorchester neighborhood. She adopted Islam, dropped out of college and bore Tamerlan's child, a daughter who's now 2 ½.

She cut off contact with her college friends after the marriage, according to the NPR report.

Tsarnaev appears to have no presence on social-media platforms such as Twitter and Facebook - practically a rite of passage for a woman of her generation. Few childhood friends and acquaintances tracked down by news outlets including Bloomberg kept in touch with her beyond high school.

One relative said her "whole path" caused friction.

"There is an estrangement in the family," Elizabeth Russell, her aunt, said in a brief phone interview April 23 from her home in Medfield, Mass. "I haven't seen Katie in four years."

Her fortunes in Cambridge after marrying Tamerlan were unlike those of many doctors' daughters. She received food stamps and welfare benefits from September 2011 to November 2012, according to a letter from the Massachusetts Department of Transitional Assistance.

Katherine worked as many as 80 hours a week as a home health-care aide, seldom seeing her husband as he cared for their daughter at home, DeLuca said.

The Tsarnaev brothers worshiped at the Islamic Society of Boston mosque in Cambridge, though Katherine Tsarnaev was never spotted there, said Anwar Kazmi, a member of the group's board of trustees.

The last time Katherine Tsarnaev saw her husband was April 18, DeLuca said, the day before he died.

Since then, she's been crying a lot, he said.

"She's very upset, very distressed. It's so hard for her, you know, she's got this little girl, she's just trying to get her mind around these events - people dying, people maimed, her husband dying," he said. "She keeps saying, 'I don't understand why this happened.'"