The FBI investigated Sheriff David Clarke earlier this year, new court documents reveal — here's why

The FBI obtained a search warrant for emails of former Milwaukee County Sheriff David Clarke earlier this year after an unusual confrontation with a passenger on an airplane.

What happened?

An FBI affidavit dated March 7 shows the FBI sought a warrant for information and communications related to Clarke's confrontation with that passenger, Dan Black, and "and the ensuing hassle Black was subjected to by deputies at Clarke's direction in the January incident," according to the Milwaukee Journal Sentinel. The warrant was for Clarke's personal Google email account.

Black filed a complaint with the Milwaukee County Executive's Office following the incident. Emails and text messages requested and obtained by the FBI reveal Clarke had six officers and two K-9's harass Black upon arriving to the Milwaukee airport from Dallas on Jan. 15. Those deputies detained Black and questioned him about comments he allegedly made to Clarke on the plane. Those officers later escorted Black out of the airport.

"Just a field interview, no arrest unless he becomes an a**hole with your guys. Question for him is why he said anything to me. Why didn’t he just keep his mouth shut?” Clarke texted one of his officers before arriving to Wisconsin, court documents released Thursday revealed.

FBI is reading Sheriff David Clarke's text messages to staff, according to search warrant affidavit. Here's one exchange after incident at airport pic.twitter.com/V6e80FBXZB

— Robert Snell (@robertsnellnews) December 29, 2017

According to the affidavit, the Audit Services Division of the Milwaukee County controller’s office determined as part of its own investigation that Clarke "used his official position as sheriff of Milwaukee County in excess of his lawful authority to direct his deputies to stop and question Black without legal justification." This included several threatening posts on the Milwaukee County Sheriff's official Facebook page.

Similarly, the FBI was investigating Clarke for possible civil rights violations.

Here's what the FBI was looking for in Sheriff David Clarke's emails pic.twitter.com/OT4gli7YNw

— Robert Snell (@robertsnellnews) December 29, 2017

What was the conclusion of the case?

Despite the evidence against Clarke, the Department of Justice informed Clarke's attorney in May that the decision had been made to not pursue criminal charges against Clarke because it would be "difficult to impossible" to prove "beyond a reasonable doubt" Clarke had committed civil rights violations.

However, as the Journal Sentinel noted, Black filed a civil rights lawsuit in federal court and it remains pending.

How did Clarke respond to the court documents going public?

Clarke told Law&Crime, a crime news website:

I am NOT currently under investigation by the FBI in the Black case. That investigation was closed back in May 2017. You’ll have to ask FBI why the return of the search warrant took so long. I was notified by Google that the search warrant request was made in March.

He later posted on Twitter blaming the "lib media" of trying to silence him with "FAKE NEWS."