Using phone data investigators since determined that Heaggan-Brown offered two other people money for sex several times last year

Heaggan-Brown later texted a mentor that he had messed up 'big time' and claimed the sex was consensual

He said he drank too much, passed out and woke up feeling drugged to find Heaggan-Brown sexually assaulting him

Victim told investigators that Heaggan-Brown bragged he was the boss while drinking at a bar while they watched TV coverage of the protests

A Milwaukee police officer who fatally shot a black man in August, sparking several nights of unrest, has been charged with sexually assaulting a man the night after the shooting, after they watched coverage of the riots on television at a bar, authorities said Thursday.

Officer Dominique Heaggan-Brown, 24, was arrested Wednesday.

The alleged victim, unidentified in a criminal complaint, told police on Aug. 15 that Heaggan-Brown had sexually assaulted him while off duty.

Heaggan-Brown fatally shot 23-year-old Sylville Smith on Aug. 13. Police said he was holding a gun when he was shot after a brief chase.

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Dominique Heaggan-Brown was arrested on Wednesday and charged with sexual assault

Police said Heaggan-Brown is suspended and in custody and they have launched an internal investigation. Police Chief Ed Flynn told reporters during a news conference that nothing in Heaggan-Brown's pre-hiring background check suggested he would be likely to engage in wrongdoing.

'It's altogether awful,' Flynn said. 'This individual has revealed his character in a way that did not come to light in the pre-hiring investigation.'

Heaggan-Brown's attorney, Michael Steinle, didn't immediately respond to messages seeking comment. Heaggan-Brown's bail was set at $100,000. He's set to appear at a preliminary hearing on Oct. 27.

According to the criminal complaint:

Heaggan-Brown took the victim to a bar late on the night of Aug. 14 where they drank heavily and watched TV as coverage of the protests aired.

The victim told investigators that Heaggan-Brown bragged that he was the boss and that there were 'no limitations' on how he lived and that he could do whatever he wanted 'without repercussions.'

The victim told police the day after the alleged assault that he had trouble remembering everything that happened after they left the bar but that he felt drugged.

Heaggan-Brown is the officer who shot dead 23-year-old Sylville Smith (pictured) in Milwaukee, Wisconsin in August

He said he woke up to Heaggan-Brown sexually assaulting him.

The complaint said Heaggan-Brown took the man to St. Joseph's Hospital early on Aug. 15. The officer told a security guard who helped him wheel the man inside that the man had had too much to drink and was 'completely out, zonked out of his gourd.'

But when nurses began providing aid, the man 'flipped out,' grabbed a security guard's arm and exclaimed: 'He raped me, he raped me,' indicating Heaggan-Brown.

Later that morning, Heaggan-Brown texted his mentor, Sgt. Joseph Hall, saying he had messed up 'big time.'

'Need your help big time. ... But need to handle this the most secret and right way possible,' the text read in part. The sergeant told investigators that Heaggan-Brown claimed the sex was consensual.

Flynn said Thursday that Hall reported his contact with Heaggan-Brown to command staff but the sergeant is under internal investigation as well. Hall remains on duty.

'We're going to get to the bottom of what that exchange was about,' Flynn said.

Using photographs and other data from the officer's cellphone, the complaint said, investigators determined that Heaggan-Brown offered two other people money for sex several times — in December 2015 and in July and August of this year — and that he sexually assaulted another unconscious person in July, and photographed that victim naked without that person's consent.

The charges include two felony counts of second-degree sexual assault, two misdemeanor prostitution counts and one felony count of capturing an intimate representation of a person without consent.

The head of Milwaukee's police union said in a statement that the facts of the case will dictate the outcome.

'The MPA condemns all criminal behavior by any member of society, whether part of this organization or not,' the union's president, Mike Crivello, said in the statement.

Heaggan-Brown joined the police department in July 2010 as an aide.

Smith's death set off several nights of protests in Milwaukee. Above, police move in on a crowd throwing rocks in Milwaukee on August 14, while Haeggan-Brown was watching tv coverage with the alleged victim

Like Smith, the man who was fatally shot, Heaggan-Brown is black. He was assigned to patrol the city's heavily minority north side.

Flynn has said that Smith was fleeing from a traffic stop when he was shot. Heaggan-Brown's body camera showed that Smith was shot after he turned toward an officer with a gun in his hand, according to investigators.

Smith's death sparked two nights of violence in the Sherman Park neighborhood, with several businesses burned. It also ramped up long-festering racial tension in Milwaukee.

The Wisconsin Department of Justice investigated Smith's death and has turned the case over to Milwaukee County District Attorney John Chisholm for a charging decision. It's not clear when a decision in that case will be made.