Those hoping the federal government will criminally prosecute Ferguson, Mo., police Officer Darren Wilson in the killing of an unarmed black man are likely to be disappointed, but chances are strong that the Justice Department will impose significant reforms on the city's police department through its ongoing civil investigation.
St. Louis County officials announced Monday that a local grand jury had found insufficient evidence to charge Wilson in the Aug. 9 shooting of Michael Brown, 18.
Some Ferguson activists hope that the Justice Department, which is conducting its own inquiry into the shooting, will file a federal criminal case against Wilson. But former civil rights prosecutors say the threshold for charging him with a federal crime is even higher than for local prosecutors because it requires proof that the officer intentionally used more force than reasonably necessary to deprive someone of his civil rights.
"It's a very tough thing under federal law to indict a police officer in a shooting," said William Yeomans, who supervised police investigations while serving as a top Justice Department official and currently teaches law at American University. "It doesn't happen very often."
Yeomans advised that Brown supporters not "put all their eggs in the criminal basket" by focusing too heavily on the outcome of the federal criminal investigation into Wilson. "The federal civil investigation into the Ferguson Police Department will continue and has the potential to result in some very significant reforms," Yeomans said.
Brown's shooting set off weeks of racially charged clashes between protesters and police. The Justice Department's civil rights division initiated two investigations, in what was seen partly as an attempt to ease tensions.
Both investigations are continuing. Justice Department officials declined to comment on the status of either.
The criminal investigation was running parallel to the St. Louis County prosecuting attorney's, with dozens of FBI agents interviewing the same witnesses who appeared before the grand jury. Although a federal grand jury is likely to be impaneled to hear evidence, few expect the criminal investigation to lead to an indictment.
"It's a very complicated case because you don't have a clear sense of what happened," said Alex Busansky, a former criminal trial attorney in the civil rights division. "There is no videotape."
Because of the high standard needed to prove police misconduct, a video can be crucial to a successful prosecution. Relying on video of the 1991 beating of Rodney King in Los Angeles, federal prosecutors convicted two of four officers charged with violating his civil rights. The federal case was filed after a Simi Valley jury acquitted the officers.
Without video, cases are usually harder to prove. A jury found four New York City police officers not guilty of second-degree murder in 2000 after they shot Amadou Diallo, an unarmed immigrant from Guinea, 19 times. A federal investigation found there was not enough evidence to charge them with civil rights violations.
The Justice Department criminal civil rights investigation into the shooting of 17-year-old Trayvon Martin in Florida in 2012 continues more than 2 1/2 years after he was killed by neighborhood watch volunteer George Zimmerman, who was acquitted in state court.
Atty. Gen. Eric H. Holder Jr., who traveled to Ferguson to listen to complaints from citizens, has said he hopes to wrap up the criminal investigation before he leaves office, possibly in February.
The broader civil investigation into the Ferguson Police Department could take longer, examining whether there is a pattern of violations of citizens' rights. These investigations can take considerable time but are more likely to yield results than federal criminal investigations, experts say.
Justice Department officials say investigators are looking into whether Ferguson police have a history of using excessive force against suspects and are examining past lawsuits against five of the city's police officers, including one in which a man with mental health problems was killed with a Taser.
They are also reviewing allegations that traffic stops occur disproportionally in black neighborhoods and that unwarranted traffic citations are fueled by the municipality's thirst for money. Traffic tickets provide a quarter of Ferguson's revenue, according to one study.
The Justice Department also is looking at the treatment of detainees in the Ferguson city jail.
St. Louis County, which includes Ferguson, voluntarily agreed to work with the Justice Department on a review of its own policing practices.
Under Holder, the Justice Department has been particularly aggressive in such investigations, opening 20 of them in the last five budget years, twice as many as under his Republican predecessors during a comparable period, according to Justice Department statistics. During the same period, it prosecuted more than 300 officers for misconduct. It has entered into formal agreements, called consent decrees, with nine departments, including New Orleans and Albuquerque.
In Ferguson and surrounding St. Louis County, they will probably be looking for evidence of excessive use of force, unreasonable searches, racial profiling in arrests or traffic stops, and other problems. The department's training and use of discipline also may be examined.
"It can go to every corner of the police department's operation," Yeomans said. Bringing a case against Ferguson should not be difficult, he added.
"We've seen there are problems and the police department's response to the protesters demonstrated some serious problems about what the police department thinks is appropriate use of force," he said. "There is a strong basis for believing that there will be systemic changes to the Ferguson Police Department."