An auction by disgraced pharmaceutical executive Martin Shkreli for his unique copy of a Wu-Tang Clan album has ended with a bid of more than US$1 million -- and plenty of questions.

The brash mogul, who bought the celebrated rap ensemble's sole edition of "Once Upon a Time in Shaolin" in 2015, last week put it up for sale. But on Wednesday he was sent to jail, with a judge revoking his bail after he threatened Hillary Clinton.

The auction ended as scheduled Friday night on eBay with a winning bid of $1,025,100 -- little moved since hitting $1 million on Sept. 7 despite a series of competing bids.

The winning bidder's identity was not known but the user's eBay profile shows that he or she has frequently sought out CDs and music memorabilia.

With Shkreli behind bars, it is unclear when or how "Once Upon a Time in Shaolin" will find its way to its buyer. Fans were already in for a wait; the Wu-Tang Clan had decreed that the music will not be available until the year 2103, although the owner is free to play it at private parties.

As the auction was winding down, questions also arose over the authenticity of "Once Upon a Time in Shaolin."

Bloomberg News in an investigation published on Thursday said it was possible that "Once Upon a Time in Shaolin" was not an actual Wu-Tang Clan album but rather an elaborate set-up by the Moroccan producer Cilvaringz, who sought out contributions from members of the group.

Shkreli, in selling the album, had voiced resentment over criticism toward him, saying he had made a gift to the Wu-Tang Clan by valuing the music.

Shkreli has been dubbed the most hated man in America after he jacked up the price of HIV drug Daraprim from $13.50 to $750 a pill overnight.

The 34-year-old New Yorker was convicted last month on unrelated securities fraud charges and had been out on $5 million bail pending sentencing.

The judge revoked the bail after he offered a reward for anyone who would grab a strand of former presidential candidate Clinton's hair -- remarks he insisted were a joke.