Former pharmaceutical chief executive Martin Shkreli has been found guilty of three counts of securities fraud.
A New York City jury cleared him on five other counts after five days of deliberations.
He was on trial in relation to a drug company he previously headed, Retrophin, and a hedge fund he managed.
Shkreli, 34, was branded “the most hated man in America” in 2015 when his firm hiked the price of a medication used by Aids patients.
Despite facing prison after being convicted of two counts of securities fraud and conspiracy to commit securities fraud, Shkreli professed himself pleased with the outcome.
Standing outside the court in Brooklyn, he said: “This was a witch hunt of epic proportions.
“And maybe they found one or two broomsticks but at the end of the day we’ve been acquitted of the most important charges in this case and I’m delighted to report that.”
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FBI investigator William Sweeney praised the conviction saying that Shkreli had “misled investors in his self-indulgent scheme”.
Shkreli rocketed to notoriety in 2015 after raising the price of a lifesaving anti-parasite drug called Daraprim by 5,000% upon acquiring rights to the medication.
Overnight, the price of the drug soared from $13.50 to $750 per dose.
Over the course of a five-week trial, jurors heard how Shkreli lied to investors about the performance of two hedge funds, MSMB Capital and MSMB Healthcare.
He then stole from Retrophin, his pharmaceutical company, to pay investors back, prosecutors said.
“Martin is a brilliant young man,” his lawyer, Benjamin Brafman, said after Friday’s ruling.
“Sometimes, people’s skills don’t translate well,” he told reporters, adding that his client suffers from “an image issue”.
During the trial, the attorney portrayed his client as a misunderstood “nerd” who turned up at work wearing a doctor’s “stethoscope and bunny slippers”.
One investor had testified that Shkreli reminded him of the autistic savant played by Dustin Hoffman in the movie Rain Man.
His attorney quoted a Lady Gaga song title in telling jurors Shkrel “was born this way”.
Shkreli’s negative press was so widely known that it took the court three full days just to find 12 jurors who did not have a pre-existing opinion of him.
Several prospective jurors were dismissed after referring to him as “a snake” and “an evil man”, the New York Post reported.
Judge Kiyo Matsumoto felt obliged at one point to issue a gag order, after Shkreli surprised reporters during a lunch break by ranting against enemies whom he said were trying to “blame me for capitalism”.
The so-called “pharma bro” often vented his spleen on social media, eventually getting himself banned from Twitter after harassing a female journalist.
He often appeared to relish in the negative publicity he received.
Shkreli was also admonished after refusing to answer questions during testimony to congressmen, whom he later called “imbeciles”.
In a bizarre coincidence, another man who is also named Martin Shkreli was arraigned before the same Brooklyn judge on Friday.
“There’s another Martin Shkreli in this case. How weird is that?” quipped one lawyer during the court proceedings.
Mr Shkreli, 59, who is accused of money laundering, told reporters about his younger doppelganger: “I don’t need that kind of fame.”