The campaign of the Republican presidential frontrunner Dr Ben Carson looked in jeopardy after he was hit by a series of allegations that parts of his life story were exaggerated and others fabricated.
Carson, a retired neurosurgeon and political newbie, described as a "witch hunt" media accusations that he lied about his college education and his violent past.
His rise from troubled, impoverished teenager in Detroit to world-renowned physician and conservative icon has been the subject of several books, a film and countless stump speeches.
But as he overtook Donald Trump in the polls last week, the only black candidate's story drew closer scrutiny. Observers and US media found discrepancies, inconsistencies and, in the latest revelations, apparent falsifications about crucial episodes in his life.
CNN published a report casting doubt on Carson's characterisation of himself in his 1996 autobiography, Gifted Hands, as a violent 14-year-old who once tried to stab a classmate. The "victim" of the episode, which Carson said was a seminal moment that led him to God, has never surfaced.
With the heat on, another damaging story emerged, contending that despite Carson having written that he was offered a "full scholarship" to West Point military academy, he never applied.
Carson called the former story a "bunch of lies", and said the latter was also dishonest because he never claimed to have applied to West Point but had been given what he took as a verbal offer of admission.
"There is a desperation on the part of some to try and find a way to tarnish me," Carson declared.
Another article suggested Carson may have invented a course which he claimed to have excelled in at Yale, and that attempts to corroborate his account of having helped white students in a race riot in Detroit were unsuccessful.
There has also been a steady stream of stories about some of Carson's more unorthodox beliefs, for example that the pyramids of Giza were built not by ancient Egyptians, but by an Old Testament figure to store grain.
Trump has responded gleefully. "The Carson story is either a total fabrication or, if true, even worse!" he said of the claims that Carson had been a violent teenager.
The rumblings about his past could stall his momentum. Trump and Senator Ted Cruz, a fellow populist Republican candidate who has been gaining traction, could benefit.
Carson reacted with fury. "What you're not going to find with me is somebody who's just going to sit back and let you be completely unfair without letting the American people know what's going on. And the American people are waking up to your games."
Telegraph Group Ltd