The death Monday of an African American man in police custody in Minneapolis has triggered a high-priority Justice Department investigation.
A video taken by a bystander showed one of the four white officers kneeling on the neck of a handcuffed 46-year-old George Floyd, who told the officer "I cannot breathe" as he was pinned to the ground for eight minutes before he died.
The four arresting officers were fired Tuesday.
On Friday, one of the fired officers, Derek Chauvin, was arrested and charged by state authorities with third-degree murder and second-degree manslaughter. It remains uncertain what federal charges if any he will face.
As state authorities in Minnesota announced Chauvin's arrest, U.S. Attorney General William Barr said the Justice Department and the FBI were investigating Floyd's death to determine whether "any federal civil rights laws were violated."
"As is the typical practice, the state's charging decisions will be made first," Barr said in a statement. "I am confident justice will be served."
Under federal law, it is a crime for a law enforcement officer to willfully deprive anyone of their constitutional rights.
Federal prosecutors rely on this statute in investigations of on-duty shootings by police officers.
But federal charges in such cases are rare. That's because the law requires prosecutors to meet a high threshold.
"You have to show the officer willfully deprived someone of their rights," explained Kanya Bennett, senior legislative counsel with the American Civil Liberties Union. "So while there is this statute that ideally should be used to hold law enforcement accountable at the federal level, when we see these horrific acts, the reality is it's very difficult to see anything that results in a conviction."
Consider a 6-year-old case that is drawing comparisons to the Floyd killing.
In 2014, Eric Garner, an African American street vendor in New York City, died after being arrested and put in a chokehold by a white police officer. His last words, like Floyd's, were "I can't breathe."
The Justice Department opened a civil rights investigation into the case that lasted several years. In the end, federal prosecutors announced they didn't have evidence to charge the officer, Daniel Pantaleo.
In announcing the Justice Department's decision last year, U.S. Attorney Richard Donoghue for the Eastern District of New York said that while Garner's death was a tragedy, investigators could not "prove that a crime was committed."
The list of police officers involved in deaths in custody who did not face federal charges includes Darren Wilson, who shot and killed Michael Brown in Ferguson, Missouri, in 2014, and Mark Ringgenberg and Dustin Schwarze, who fatally shot 24-year-old African American Jamar Clark in Minneapolis in 2015.
A rare exception was Michael Slager, a white former South Carolina police officer who was indicted on federal civil rights charges in 2016 after a state jury failed to convict him in the fatal shooting of 50-year-old African American Walter Scott in 2015. Slager was convicted and sentenced to 20 years in prison in 2017.
'Pattern and practice' of misconduct
While the Justice Department often can't criminally charge police officers involved in on-duty deaths, it has the ability to investigate, and where necessary bring civil rights charges against, police departments with "a pattern and practice" of misconduct.
Under the Obama administration, the Justice Department opened two dozen investigations into police departments accused of abuse and misconduct, entering into 14 court-imposed reform agreements known as "consent decrees" with cities across the country.
Proponents such as the U.S. Commission on Civil Rights say consent decrees are "necessary to ensure that constitutional policing standards are upheld."
But investigating police misconduct has not been a priority for the Trump Justice Department. Trump's first attorney general, Jeff Sessions, effectively ended the department's decades-long practice of entering into consent decrees with cities, calling it an insult to local jurisdictions.
Barr appears to have kept the Sessions policy in place. A Justice Department spokesperson did not respond to questions about the department's current policy on consent decrees and whether it has investigated any police departments since 2017.
Trump, who campaigned on "ending the war on our police," has made supporting law enforcement a priority for his administration. In January, he signed an executive order to establish a commission to study issues affecting police officers, lamenting "a continued lack of trust and respect for law enforcement that persists in many communities."
Kristen Clarke, president of the Lawyers Committee for Civil Rights Under Law, said the Floyd killing represents "a powerful and tragic reminder of the problem of systemic police violence in our country too often perpetrated against African Americans who are unarmed and not violent."
Chauvin, the officer accused of killing Floyd, has been involved in at least three shootings and has had nearly 20 complaints lodged against him.
Clarke said holding the officers involved in the death accountable is as important as addressing "systematic problems infecting this police department."
"The community deserves safety and deserves the police department they can trust," Clarke said. "And no doubt there is a lot of work to be done here."