Controversial pro-Trump lawman David Clarke has resigned his post as Milwaukee County sheriff.

“I have chosen to retire to pursue other opportunities”, Mr Clarke said in a statement to the media. “I will have news about my next steps in the very near future”.

As criticisms of police officers killing suspects galvanised waves of protests and birthed the Black Lives Matter in recent years, Mr Clarke, who is African-American, positioned himself as the defender of a besieged profession.

He condemned “anti-police rhetoric” and called Black Lives Matter a “terrorist movement”.

That stance aligned with Donald Trump’s law-and-order platform, helping to win Mr Clarke a speaking spot at the Republican National Convention last summer in which he opened his speech with the line “blue lives matter” and lauded a Baltimore police officer’s acquittal in the case of a suspect who died in custody.

Mr Clarke has remained a stalwart supporter since Mr Trump won the election, frequently appearing on Fox News to defend the President’s actions.

He was reportedly under consideration for a post at the Department of Homeland Security but withdrew himself from the running.

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The former sheriff has also embraced Mr Trump’s effort to enlist local governments in cracking down on illegal immigration, seeking earlier this year to participate in a federal program that deputises local authorities to help enforce immigration laws.

His tenure was marred by the deaths of inmates in jails under Mr Clarke’s jurisdiction. An inquiry into the death of a mentally ill inmate who died from dehydration in a Milwaukee County jail led juror to recommend criminal charges.