(TNS) -- Modern video technology collides with a post-Civil War law and a 1945 Supreme Court ruling when it comes to prosecuting police officers for assaulting and killing unarmed suspects.

Videos record actions, but do not always demonstrate whether an officer “willfully” intended to violate someone's civil rights, prosecutors and legal experts said.

“There's no question in any particular case if we have a video, it might be very, very strong evidence of a crime,” said Steve Kaufman, chief of the criminal division for the U.S. Attorney's Office for Western Pennsylvania in Pittsburgh. “... But we sometimes have to decline cases that have video if the video doesn't show that a crime occurred.”

A Tribune-Review investigation of nearly 3 million records found that Department of Justice prosecutors declined to bring charges in 96 percent of civil rights complaints against law enforcement officers across the United States and its territories between 1995 and 2015.

Western Pennsylvania prosecutors follow that trend, declining to prosecute 96 percent of 185 civil rights complaints involving police officers, the Trib found.

As small, high-quality cameras have become ubiquitous on every smartphone, video has become a larger factor in the public demanding accountability from police-involved incidents across the country.

David Hickton, the U.S. Attorney for Western Pennsylvania, cited an April 2015 video of a white police officer in North Charleston, S.C., shooting an unarmed, fleeing black man in the back as one of the most distressing examples.

Yet civil rights cases against police officers are hard to prosecute, said Craig Futterman, a law professor at the University of Chicago who founded the Civil Rights and Police Accountability Project there.

Prosecutors have declined to charge officers or have failed to convince a jury of the officer's intent, he said.

In fluid situations, and depending on the circumstances, it can be difficult to prove what anyone meant to do — even with video, Hickton said.

“When you take sort of a loosely defined accidental encounter at a traffic stop ... it's very difficult starting at that point to get over the intent requirement we face under that statute,” he said. “It was really built for a time when someone went out with a specific intent to do someone harm.”

The underlying law — Title 18, Section 242 — dates to 1866. The requirement that officers must “willfully” intend to violate someone's civil rights stems from a 1945 Supreme Court ruling. Both grew out of Southern racial tensions.

Hickton declined to discuss specific cases or to recommend changes to update the statute, saying his job as a U.S. attorney is to enforce the laws — not make them.

But Hickton acknowledged he was so concerned about the high standard for police civil rights cases that he brought up the issue with then-U.S. Attorney General Eric Holder. Holder talked about proposing changes but left office last year without doing so.

In addition to proving intent, federal prosecutors are directed to bring cases only when they can prove a defendant's guilt beyond a reasonable doubt.

“You should bring them if you are convinced it's the right thing to do — and you're convinced you can win,” said Mark Pomerantz, a former federal prosecutor in New York City. “To bring them and lose them doesn't serve anyone's interests.”

Shaky and blurry

The video seems almost unwatchable by today's smartphone standards: shaky, blurry and somewhat dark.

But the images from 1991 of Los Angeles police officers beating Rodney King with nightsticks and kicking him were vivid enough for a jury to conclude the police had crossed a line, said Harry Litman, then a federal prosecutor who worked on the case.

“You were able to really break things down and show a point in the beating where the officers must have known that they were using an unreasonable amount of force,” Litman said.

Seven years after the King incident, Litman returned home to Pittsburgh as the U.S. attorney for Western Pennsylvania. One of his first jobs was announcing in February 1999 that his office would not charge five suburban police officers in the death of Jonny Gammage, an unarmed black motorist killed during a traffic stop.

Gammage had been driving a Jaguar owned by his cousin, Steelers defensive end Ray Seals, when he was pulled over in October 1995 by a Brentwood police officer, just inside the Pittsburgh city limits. As officers scuffled with him and then pinned him to the ground for an arrest, Gammage suffocated.

Litman and prosecutors from the U.S. attorney's office and Justice Department looked at all the available evidence and determined they didn't have enough to meet the standard of proof that the officers meant to kill Gammage, Litman said. Unlike the King incident in Los Angeles, no video existed of the Gammage arrest.

“The best thing is that a video shows the officer's actions but it also shows whether the victim is presenting a reasonable threat to them,” Litman said. “There's often in the absence of video very conflicting testimony about what the victim was doing at the time.”

A similar murkiness remains about what happened when undercover Pittsburgh police officers arrested performing arts student Jordan Miles in Homewood in January 2010. No video exists to show how Miles, who lived in the neighborhood and was unarmed, ended up with a badly bruised and swollen face.

Again, federal prosecutors said they lacked evidence to prove officers acted willfully to harm Miles.

“I have concluded that the evidence in this case will not support the heavy burden of a criminal charge against the officers,” Hickton said in May 2011.

Miles sued the three officers for violating his civil rights. Two juries found for the officers on malicious prosecution and excessive force claims, but the jurors agreed that the officers lacked probable cause for the arrest. A lawyer for one of the officers and a lawyer for Miles said they were unsure how much a video would have affected either Hickton's decision not to charge the officers or the verdicts in the two civil trials.

Video from smartphones, security cameras or even today's police dashboard and body cameras would have helped lawyers on both sides of the incident better establish what happened, said Beth Pittinger, executive director of the Citizen Police Review Board of Pittsburgh, an independent agency that investigates complaints of police misconduct.

“It would be a whole different story,” Pittinger said. “We would be able to assess the circumstances of that encounter from the get-go. We wouldn't know the nuances or what the officers knew when they arrived on the scene, but we would have a much better impression of how that encounter went down.”

Video often proves that the truth of what happened does not always get written into the official reports, she noted.

Police incidents often present conflicting testimony from officers and defendants, said Frederick Thieman, the U.S. attorney for Western Pennsylvania from 1993 to 1997. Technology can help prosecutors resolve those differences.

“The better the evidence, the better the case,” Thieman said. “The proliferation of recording devices, smartphones and everything else has certainly provided an opportunity for corroborating evidence that can make a case, or show that a case absolutely shouldn't be brought.”

‘It's not perfect'

Thomas Jason James Smith, then 28, didn't know that Millvale police Officer Nicole Murphy violated his civil rights when she used a Taser on him while he sat on the floor of the police station, said his criminal defense attorney, David J. Shrager.

Arrested for public drunkenness, disorderly conduct and resisting arrest, Smith has a learning disability that kept him from understanding he had a right not to be assaulted while he sat shirtless with his hands cuffed behind his back, Shrager said.

The FBI started investigating the Millvale incident when video shot by another officer was sent to Shrager and the Tribfour months later in January 2013.

Without the video, a prosecution of Murphy would have come down to her version of events versus Smith's version of events, Shrager said. While federal prosecutors might still have charged her, “the outcome may have been different,” he said.

“Most citizens trust and believe the police and rightfully so,” Shrager said. “When something does happen that is negative and contrary to the way police behave, having a video is important because it gives credibility to a person who may otherwise be ignored or disbelieved.”

Video is often blurry, shot from a bad angle, or in bad lighting and sometimes doesn't have sound.

“It's not perfect. However, it is better than eyewitness testimony, usually,” Shrager said.

Hickton's office charged Murphy with interfering in Smith's civil rights. A federal jury convicted her in November 2014. She was sentenced to three years of probation and 300 hours of community service. Murphy on Friday filed an appeal of her conviction.

Millvale paid Smith $37,000 in 2014 to settle a civil suit he filed.

“Law enforcement officers are sworn to uphold and obey the law,” Hickton said after the conviction. “Nicole Murphy did neither ... thereby violating his civil rights.”

©2016 The Pittsburgh Tribune-Review (Greensburg, Pa.) Distributed by Tribune Content Agency, LLC.

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