A police chief in the US state of New Jersey compared African Americans to the Islamic State of Iraq and the Levant (ISIL) armed group and expressed his desire to "mow 'em down" in a firing squad, according to a federal lawsuit.

Sixty-year-old Frank Nucera Jr, who was the police chief of the Bordentown Township Police Department (BTPD) until earlier this year, has been charged with a federal hate crime and other civil rights offences.

The charges were unsealed on Tuesday.

The lawsuit, seen by Al Jazeera, alleges that Nucera slammed the head of an African American suspect, who is not named in the documents, "into a doorjamb, causing bodily injury".

The lawsuit also describes a worrisome pattern of racist remarks, including referring to African Americans as "n*ggers", "n*gs" and "m*ulies".

Nucera retired from the force in January under "mysterious" circumstances, The Trentonian, a local newspaper, reported at the time.

Likening African Americans to ISIL (also known as ISIS), Nucera reportedly expressed his desire to subject them to a firing squad while speaking to a subordinate officer.

"I wish that n*gger would come back from Trenton and give me a reason to put my hands on him, I'm tired of 'em," he said of an African American believed to have slashed the tires of a police vehicle in November 2015, according to the lawsuit.

"These n*ggers are like ISIS; they have no value. They should line them all up and mow 'em down. I'd like to be on the firing squad; I could do it. I used to think about if I could shoot someone or not, I could do it, I'm tired of it."

Using dogs for intimidation

At the time of publication, Tracy Riley, Nucera's lawyer, had not replied to Al Jazeera's request for a comment.

Nucera appeared in court on Wednesday and was released after making bail, which was set at $500,000, according to court transcripts.

The lawsuit further accuses the former police chief of using police dogs to intimidate African Americans.

In one instance, the lawsuit says, Nucera instructed officers to bring dogs to basketball games where the police department provided security to "intimidate African American patrons".

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On April 30, 2016, Nucera allegedly ordered an officer to walk a canine through an apartment complex to "let these f*cking m*ulies see him".

Later that year, on September 1, the former police chief responded to a call for backup at the Bordentown Ramada hotel, where two officers had been in an altercation with two teenage African American suspects alleged to have not paid for their accommodation.

The lawsuit says that Nucera slammed an 18-year-old suspect's head into a doorjamb although he was "handcuffed and no longer resisting" arrest.

An unnamed police officer cited in the lawsuit "did not report Nucera's use of force, even though he viewed it as excessive, because he was afraid of retaliation from the defendant".

The teenager asked to be hospitalised initially, but he subsequently changed his mind and was taken to jail, the federal complaint says.

'Lack of accountability'

The lawsuit comes at a time when civil rights groups and watchdogs are criticising right-wing US President Donald Trump for ostensibly urging police officers to engage in police brutality and excessive force.

While addressing police officers in New York's Suffolk County in August, Trump told them not to be "too nice" while putting "thugs in the back of a paddy wagon".

Trump went on to tell the officers to "take the hand away" rather than shielding the heads of handcuffed suspects while putting them in police vehicles.

Jose Woss, legislative manager at the Friends Committee on National Legislation, explained that Trump's comments speak to a broad segment of society that believes it is permissible to behave violently to people suspected of crimes.

"It's not to say that all cops are bad, but there are serious systemic problems in society, and that's also the case in policing," he told Al Jazeera by telephone, alluding to a complex web of factors that disproportionately impact African Americans in the country's justice system.

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Although African Americans account for some 12 percent of the population, they make up roughly a quarter of those killed by police officers last year, according to The Counted, a database maintained by The Guardian.

Mapping Police Violence, a watchdog group, says that 99 percent of police officers who used deadly force in 2015 were not convicted of a crime.

That group has documented at least 964 people killed by police so far this year.

"Policing hasn't changed much in America over the last century, with the exception of some protections in the Civil Rights era," Woss added. "It's really easy for the average American to not see this as a problem."

He said: "The history of a lack of accountability bears this out. It's incredibly difficult to not only indict but convict someone who is guilty of essentially murder."