Man joining Trump administration said Black Lives Matter and Isis were teaming up to destroy America

Milwaukee County Sheriff David A. Clarke has said he will join the Trump administration as an assistant secretary to the Department of Homeland Security (DHS).

Mr Clarke – a prominent, controversial Trump surrogate during the 2016 campaign – made the announcement to conservative radio host Vicki McKenna. Mr Clarke said he will work in the Office of Partnership and Programs, which coordinates outreach efforts to local authorities.

"I'll be a liaison with state and local governments, with the private sector and – one that's really near and dear to me – liaison to state and local and tribal law enforcement," Mr Clarke said.

A former Obama-era DHS official, Phil McNamara, tweeted on Wednesday that he was being replaced by Mr Clarke.

"My job was to work with state and local officials. Clarke says he wants to strangle #Democrats," Mr McNamara wrote.

The DHS website, however, currently lists the assistant secretary position as “vacant”. A DHS spokesperson told CNN that "no such announcement with regard to the Office of Public Engagement has been made."

Aside from his role as Milwaukee county sheriff, Mr Clarke is perhaps best known for his controversial political statements. He maintains a prolific Twitter account, where he has encouraged Americans to take up “pitchforks and torches” against the government and suggested that Black Lives Matter will soon join hands with Isis to bring down America.

At one point, Mr Clarke compared former President Barack Obama's management of the Department of Justice to Adolf Hitler consolidating all police forces under one commander.

In his memoir, Mr Clarke suggested that anyone suspected of terrorism should be treated as an “enemy combatant,” and held indefinitely. He expanded on this viewpoint on his radio show, The People's Sheriff, where he suggested arresting anyone who expressed pro-terrorist sentiments and sending them to Guantanamo Bay, the United States’ offshore military prison.

At the time, Mr Clarke estimated the number of people who should be detained at Guantanamo Bay could be up to “maybe a million”.

“We're at war. This is a time of war,” he said. “Bold and aggressive action is needed."

The Milwaukee County jails Mr Clarke oversees are currently under investigation for four deaths transpiring in 2016. In one case, a mentally ill inmate died of dehydration after being denied water for seven days. In another case, a mother and her newborn baby died after allegedly being denied care.

Peter Koneazny, an attorney with Legal Aid Society of Milwaukee who is involved in litigation against the jails, says he is concerned about the management of the jail, the quality of care, and the treatment of inmates.

“The deaths do raise a lot of questions in terms of the training and supervision of people within his department, and they’ve had a lot of staff turnover,” Mr Koneazny told the Huffington Post.

In response to the allegations, Mr Clarke has said, “We'll see them in court”.

Mr Clarke’s DHS role, unlike a Cabinet nomination, will not require Senate confirmation. He said he plans to assume the role in June.