Updated: 4:28 p.m. ET
(CBS News) Nearly a month after questions were first raised surrounding Elizabeth Warren's past claims to Native American lineage, the Democratic Massachusetts Senate candidate continues to be dogged by a debate over whether or not she improperly identified as Native American in order to further her professional career.
Despite attempts by the Warren campaign to downplay the controversy, a new report Friday by the Boston Globe calls into question the veracity of Warren's recent claim that she had been unaware Harvard Law School touted her as a Native American employee during her tenure there.
"I think I read it on the front page of the Herald," Warren said in late April, when asked about Harvard's having promoted her purported minority status.
According to the Globe, Harvard reported for six years during Warren's tenure at the school that a Native American woman was among its senior law professors. "According to both Harvard officials and federal guidelines, those statistics are almost always based on the way employees describe themselves," writes the Globe's Mary Carmichael.
The story also alleges that Warren fails to meet both federal and school-wide standards that would qualify her to formally list herself as a Native American.
Generally speaking, the federal government does not officially recognize a person as an American Indian unless he or she has had status conferred upon them by one of 566 federally recognized tribes. A Certificate Degree of Indian Blood (CDIB) can also be obtained to prove that a person has Native American blood, though it does not confer tribal status.
According to the Globe, Harvard characterized a Native American as "a person having origins in any of the original peoples of North America and who maintains cultural identification through tribal affiliation or community recognition.''
"I am proud of my family and I am proud of my heritage," Warren told reporters on Thursday, according to MassLive.com, after being questioned repeatedly on the issue.
When asked how she knew she had a Native American background, Warren cited family lore.
"Because my mother told me so. This is how I live. My mother, my grandmother, my family. This is my family. Scott Brown has launched attacks on my family. I am not backing off from my family," she said.
Warrenof "the stories that my grandparents told me that my grandparents told my parents and my parents told my brothers and me," with regard to her heritage, and has cited a photo of her grandfather, who she said "had high cheek bones like all of the Indians do."
But despite having listed herself as a Native American in a directory of law professors for several years between the 1980s and 1990s, Warren has failed to produce evidence substantiating her Native American lineage.
Brown, the incumbent Republican senator, said in a statement Friday that he was "offended" by the accusation that he had attacked Warren's family "when I have done nothing of the kind."
"To make that kind of wild and baseless charge is disturbing," he said. "This Native American controversy is a problem of Elizabeth Warren's own making. She falsely described herself as a minority and some of the schools where she worked relied on that information to misrepresent the diversity of their faculty."
Brown called on Harvard to "correct the record" regarding Warren's heritage.
"The Boston Globe today has a story that states that Harvard may have violated federal guidelines in the reporting of diversity information because of what Elizabeth Warren told them. I call on Harvard President Faust to immediately correct the record with the relevant federal agencies and uphold Harvard's 400-year-old tradition of abiding by the truth," the statement said.
In an e-mailed statement to Hotsheet, Warren spokesperson Alethea Harney argued that Warren has already "answered countless questions" about her heritage and that "it's time to focus on the important issues."
"Over the past month Elizabeth has answered countless questions openly while the people who recruited her have made it clear it was because of her extraordinary skill as a teacher and a groundbreaking scholar," Harney said. "She is proud of her family and her heritage, and it is something that her family talked about often when she was growing up."
Harney added: "The fact that Elizabeth noted her heritage in a professional publication has been made public and addressed by Elizabeth on multiple occasions. It's time to focus on the important issues facing Massachusetts. Republican Senator Scott Brown is trying to distract people from his record voting for Wall Street, big oil and big increases in student loans. There are real issues middle class families are dealing with every day and that's where Elizabeth is focused."
Despite the ongoing controversy, a recentshows the Democratic candidate locked in a neck-and-neck race with Brown.