Milwaukee County Sheriff David Clarke has handed over his resignation letter and the reasons why he has decided to leave his job are yet unknown, according to local media reports.

A few months ago, Clarke would have considered resigning to his post and join the Department of Homeland Security as an assistant secretary, but he eventually rejected the offer, declaring that, "he believed his skills would be best used by promoting the president's agenda in a more aggressive way".

Clarke has been a strong supporter of President Donald Trump since his presidential campaign, and was considered a potential figure within the administration, until charges were made public against him for having plagiarized several paragraphs in his thesis within the Naval Postgraduate School.

Also, during the year 2016, three people died inside the Milwaukee County jail, under the supervision of Sheriff Clarke. One of them, Terrill Thomas, died due to dehydration, which was considered "essentially torture", by activist groups like Voces de la Frontera.

Despite his record, his "loyalty" to President Trump never faltered, and his surprise resignation on Thursday leaves everyone waiting for his next move.