Former San Diego Mayor Maureen O’Connor is attributing her large-scale gambling addiction, in part, to a brain tumor.

O’Connor, widow of Jack in the Box founder Robert Peterson, inherited nearly $50 million after her husband’s death, some of which she dedicated to a charity in his name. She first used her savings to feed her gambling. Once those ran out, she began selling properties to gain more capital. When her personal funds ran dry at the video poker machines, O’Connor raided the charity and stole $2.1 million.

In total, O’Connor lost more than $1 billion.

U.S. Department of Justice federal prosecutor Phillip Halpern, remains skeptical that the brain tumor triggered O’Connor’s gambling addiction, because her gambling streak began in 2001—a decade before the tumor.

“We’re talking about billions with a ‘B,’” Halpern said in an interview with CBS News. “It’s not against the law to bankrupt yourself. The violation was that she raided that charity of $2 million.”

The golf ball-sized tumor was detected and removed in 2011 after O’Connor said she began having hallucinations.

“It’s not an excuse for my gambling, but I think that was, yes, a part of it,” O’Connor told CBS News. “You lose your sense of control.”

O’Connor’s claim is not unprecedented or unfounded. There have been cases where brain tumors have altered a person’s personality or habits, sometimes drastically.

In 2003, a 40-year-old teacher in Charlottesville, Va. began collecting child pornography and making sexual advances toward female students. After attempting to molest his stepdaughter, he was arrested. Doctors discovered a brain tumor the day before his sentencing; his deviancy ceased after the tumor was removed, although it resurfaced when the growth returned.

“I think it’s like real estate: location, location, location,” Dr. Howard Shaffer, associate professor of psychiatry at Harvard Medical School told Time Magazine. “If (a tumor) is in a frontal area it might disturb organization or braking mechanisms. If it’s in another region, like closer to the ventral tegmental era, it might have more to do with energizing impulses.”

According to University of Pennsylvania Psychology law professor Stephen Morse, the tumor wouldn’t make her less responsible for her actions.

“If it could be shown that it in part produced a genuine excusing or mitigating condition, such as diminished rational or control capacity, then it would strengthen the case for lesser responsibility because the cause of the excusing or mitigating condition was not her fault, at least in part,” Morse said.

Although O’Connor said she considered the money a loan she would repay, Halpern considers it money laundering.

Halpern said the Justice Department may drop the charges if O’Connor repays the charity and seeks help for her addiction.