The sister of the Boston bombing suspects said "I have no idea what got into them" and described the two as "great people," the Star-Ledger reported.
The woman, who has not been identified, spoke to the newspaper's reporters from behind the door of her apartment in West New York, N.J., on Friday.
"He was a kind and loving man," the woman said of her older brother. "I'm sorry for the families that lost their loved ones the same way I lost my loved one."
"This is very hurtful," she said, adding that she hadn't seen her brothers in a long time.
Another person, who identified himself as the woman's husband, told the newspaper through a crack in the door that "I'm not Muslim and they didn't accept me so I never met them."
Federal agents from the FBI Joint Terrorism task force swarmed the woman's apartment by late morning, roping off three blocks around the building.
Caridad Rodriquez, the West New York Police Department Police Commissioner, confirmed to reporters at the scene that the woman living in the building is the sister of the suspects.
Authorities are investigating whether she has any other family members in that town, he said.
"For all we know, she may be a bystander like the rest of us," Rodriquez said of the woman.
"She wants privacy because she has said that her and her family have nothing to do with the bombing," he said.
FoxNews.com's Perry Chiaramonte contributed to this report.