WASHINGTON (AP) — A retired neurosurgeon, Ben Carson has often recounted his childhood as the son of a single mother in inner-city Detroit. In his 1996 autobiography “Gifted Hands,” Carson wrote of the humiliation he felt using food stamps from his mom to pay for bread and milk, and said he began to excel at school only after receiving a free pair of glasses that allowed him to see the lessons written on chalk boards.

After Carson’s mother divorced his father, she received a small house in the settlement. But as her financial situation deteriorated, Carson and his siblings were forced to move into a succession of tenements and apartment buildings, some of which he described as having “hordes of rats” and “armies of roaches.”

Carson has not said whether his family ever lived in federally funded housing or received Section 8 subsidies to help pay rent, but as a political figure he has criticized such public assistance programs for creating “dependency” on the government among low-income minorities.

“I’m interested in getting rid of dependency, and I want us to find a way to allow people to excel in our society, and as more and more people hear that message, they will recognize who is truly on their side and who is trying to keep them suppressed and cultivate their votes,” Carson said in a speech at the Conservative Political Action Conference in 2015.

With the help of financial aid and scholarships, Carson attended Yale University and the University of Michigan Medical School before being the first African-American named as the head of pediatric neurosurgery at Johns Hopkins Children’s Center in Baltimore. There, he garnered national acclaim for directing the first surgery to separate twins connected at the back of the head.

Carson’s rise to political prominence began with a 2013 speech at the National Prayer Breakfast, where he gave a withering critique of the modern welfare state and the nation’s overall direction while President Barack Obama was seated just feet away. During the 2016 Republican presidential primary, Carson’s inspirational life story, Christian faith and anti-establishment message briefly catapulted him last year ahead of Trump and other rivals in opinion polls.

But his success on the campaign trail quickly crumbled amid questions about whether elements of his rags-to-riches autobiography were exaggerated or fabricated — including a purported childhood fit of rage he tried to stab his best friend in the belly only to be foiled by a belt buckle. Carson’s business dealings also faced scrutiny, including his ties to a wealthy Pittsburgh dentist whom he helped avoid prison time for felony health care fraud.

The Associated Press first reported last year that Carson invested millions of dollars in real estate deals with Alfonso A. Costa, whose dentistry license was revoked following a felony conviction. According to required financial disclosure forms he filed in 2015, Carson his wife made between $200,000 and $2 million a year from those real estate investments. Costa also served on the board of Carson’s charity, the Carson Scholars Fund, which provides college scholarships to children in need.

Records show Carson appeared as a character witness at his friend’s 2008 sentencing hearing, pleading with the judge for leniency. Though he faced up to 10 years in prison, Costa received a greatly reduced sentence of one year of house arrest served in a suburban mansion. Yet in his 2013 book “America the Beautiful,” Carson called for severe penalties for those convicted of health care fraud, including at least a decade in prison and “the loss of all of one’s personal possessions.”