Milwaukee County Sheriff David Clarke, an outspoken supporter of President Donald Trump and one of the nation’s most controversial law enforcement officials, plagiarized sections of his master’s thesis, according to a report by CNN.

According to the report by CNN’s KFILE, there are at least 47 instances in Clarke’s 2013 thesis on national security where he failed to attribute his sources correctly.

Sources Clarke plagiarized include a 2002 ACLU report about “The Government’s Demand for New and Unnecessary Powers After September 11,” a 2003 ACLU report critical of the FBI’s records-collection practices, a 2007 ACLU report on “fusion centers,” and a 2011 ACLU report on the need to overhaul secrecy laws. Other sources Clarke lifted words from include: the 9/11 Commission Report, a 2011 article in the Homeland Security Affairs journal, the Pew Research Center, a 2012 report by the Constitution Project, a 2003 report by the US General Accounting Office, a 2011 Brennan Center report, a 2013 Washington Post article about the Foreign Intelligence Surveillance Court, Comparative Homeland Security: Global Lessons, a textbook by Nadav Morag, and Safe Cities Project, a research paper published by the Manhattan Institute. Clarke also lifted language from former President George W. Bush’s book, “Decision Points.”

Read CNN’s full report.

Clarke on Wednesday claimed that he had accepted a position with the Department of Homeland Security as an assistant secretary.

DHS appeared to push back on that claim shortly afterward, saying that “no such announcement” has been made with regard to the position in question.

Prospective members of Trump’s administration have previously faced allegations of plagiarism.

CNN reported in January that Monica Crowley, Trump’s pick for a top national security communications position, plagiarized large parts of her 2012 book. Days later, Politico reported that Crowley also plagiarized multiple sections of her doctoral dissertation in international relations. Crowley later announced that she would not join Trump’s administration after all.

The Washington Post in January flagged entire phrases and sentences that Betsy DeVos, Trump’s pick for secretary of education, apparently used without attribution in her written responses to a Senate questionnaire.

Clarke’s tenure as sheriff was controversial before questions of plagiarism arose, as multiple inmates have died in the jail he runs in Milwaukee County.

Earlier in May a jury recommended charges against seven officials at the jail after an inmate was deprived of water for seven days straight and died of dehydration. And in March, the Associated Press reported that four people — including a newborn baby — died at the jail within a six-month period last year.