Milwaukee County Sheriff David Clarke announced on Wednesday he had accepted a position as assistant secretary at the Department of Homeland Security. The announcement cast new light on Clarke's controversial past and colorful Twitter history.

For starters, in 2015 Clarke compared former President Obama to Hitler and called on people to "wake up!"

And in 2014, Clarke claimed that "Al Sharpton has ruined more Black minds than has crack cocaine."

In March, Clarke shared a story about the murder of a DNC staffer, and wondered if he was "killed because he knew too much" — a popular conspiracy theory that has been discredited.

Clarke also has ties to Russia and — rather oddly for someone who was a county sheriff in Wisconsin — met years ago with Russian officials in Moscow.

Clarke tweeted about visiting Moscow in December 2015, saying he met with Russia's foreign minister. According to the Daily Beast, Clarke visited the country as part of a delegation from the National Rifle Association. The delegation reportedly met with Dmitry Rogozin, a far-right official who was under US sanctions.

Clarke's trip was paid for by both a firearm company CEO, and an organization run by a Russian national based in Washington, DC.

His connections to Russia are likely to raise eyebrows, given ongoing questions about ties between Trump's campaign and the Kremlin, as well as recent revelations that Trump pressured FBI Director James Comey to halt an investigation related to Russia. Trump later fired Comey.