Milwaukee County Sheriff David Clarke, who says he's been appointed an assistant secretary in the Department of Homeland Security, has denied he plagiarized content in his master's thesis on homeland security, while the Naval Postgraduate School confirmed Sunday that it's reviewing the allegations.

The denial followed a CNN report Saturday saying Clarke, who built a following among conservatives with his provocative social media presence and strong support of President Donald Trump, failed to properly attribute his sources at least 47 times in his 2013 thesis, titled "Making U.S. security and privacy rights compatible."

Clarke wrote in an email to The Milwaukee Journal Sentinel that "only someone with a political agenda would say this is plagiarism."

The Department of Homeland Security hasn't confirmed Clarke's appointment as assistant secretary, which the tough-talking, cowboy hat-wearing sheriff announced Wednesday during an appearance on a Wisconsin radio talk show. Clarke said he would act as a liaison between DHS Secretary John Kelly and state and local government officials, including mayors and law enforcement, as well as people in the private sector.

The Naval Postgraduate School in Monterey, Calif., removed his thesis from its online archive on Friday, Lt. Cmdr. Clint Phillips, a school spokesman, told The Associated Press on Sunday.

The CNN report said Clarke lifted language from several sources, and footnoted those sources, but did not use quotation marks to show he had used passages verbatim, despite school guidelines saying that material quoted word-for-word must be set off with quotation marks, or presented as indented text for longer passages, and be followed with a proper citation.

Clarke's thesis was replaced on the school's online archive with a message saying, "This item was removed from view at the discretion of the Naval Postgraduate School." The message directed viewers to the archive's policies page, which listed several potential reasons for taking an item down, including not meeting "the School's guidelines for plagiarism, research methodology or integrity of research."

A Sheriff's Department spokeswoman, Fran McLaughlin, told the newspaper that Clarke followed the school's system for writing papers and that the CNN report was biased. She declined to provide additional information when asked by the AP on Sunday, saying in an email, "The sheriff said to follow national media for his response to this smear."

Phillips said the Naval Postgraduate School's "standard operating procedure" is to take down a thesis anytime questions are raised about its validity while the school conducts an internal academic review. He said that review will be "very thorough," and declined to speculate on how long it will take or the potential consequences for Clarke.

"I can't comment on the status of his degree or even on the status of the thesis at this point," he said.

The school's 2013 and 2017 honor codes define plagiarism as "Submitting material that in part or whole is not one's own work without proper attribution. Plagiarism is further defined as the use, without giving reasonable and appropriate credit to or acknowledging the author or source, of another person's original work. ..."

It was a time of turmoil for Clarke and the sheriff's office even before the job announcement and the plagiarism allegations. Seven workers at the county jail he oversees are at the center of a criminal investigation into the dehydration death last year of an inmate who prosecutors say was deprived of water as punishment.

The Milwaukee County prosecutor's office is considering charges against those staffers, based on a jury's recommendation after a weeklong inquest. Clarke wasn't among the seven because prosecutors say he wasn't directly involved in the events leading up to the inmate's death. But the death happened under his leadership, which his critics say was sufficient cause for Clarke's firing.

