Notorious former pharmaceutical company boss Martin Shkreli has been called a "danger to society" and jailed after he offered US$5000 for a sample of Hillary Clinton's hair.
Shkreli was on bail after being found guilty on multiple counts of securities fraud.
Last week, Shkreli told followers on his Facebook to take Ms Clintons hair.
"On HRC's book tour, try and grab a hair from her," he wrote. "I must confirm the [DNA] sequences I have. Will pay $5,000 per hair obtained from Hillary Clinton."
He later apologised, saying he had quickly changed his post to make clear he had just been joking.
"I wanted to personally apologize to this court and my lawyers for the aggravation that my recent postings have caused," Shkreli wrote in a letter on Tuesday (local time).
"I understand now that some may have read my comments about Mrs Clinton as threatening, when that was never my intention when making those comments."
"I used poor judgment but never intended to cause alarm or promote any act of violence whatsoever."
However it was too late. The Secret Service launched an inquiry, and the prosecutors asked for Shkreli to be jailed, saying "his recent public conduct demonstrates that he cannot meet his post-trial burden to show, by clear and convincing evidence, that he does not pose a danger to the community".
On Wednesday (local time) a federal judge revoked his US$5 million bond. Shkreli will now stay in custody until his sentencing on his fraud charges.