The Internal Revenue Service (IRS) is seeking more than $4.6 million in unpaid taxes from former Turing Pharmaceuticals CEO Martin Shkreli, Gawker reported on Thursday.

The agency filed a lien against Shkreli in New York City last month, seeking $4,625,496.70 in taxes from 2014, as well as $3,431.85 in unpaid taxes from 2013. Neither Shkreli nor his attorney have commented regarding the matter.

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Gawker also posted a picture of the document, which can be seen below.

Shkreli, who became known as “Pharma Bro” after hiking the price on a cancer treatment drug from $13.50 a pill to $750 a pill, also faces a $2 million lawsuit from artist Jason Koza, who argues that his artwork was illegally featured in a Wu-Tang Clan album Shkreli said he bought because he wanted to “keep it from the people.”

The former hedge fund investor also suffered a $40 million trading loss in an account used to track his bail following his arrest on securities fraud charges.