Police in the United States shoot and kill about 1,000 people a year, according to a Washington Post database
The case against Derek Chauvin looked formidable. Video footage captured him with his knee pressed against George Floyd's neck for more than nine minutes.
Former Minneapolis police colleagues testified against Chauvin. Medical experts convincingly tied Floyd's death to Chauvin's use of force.
But, legal experts said, Chauvin had one big factor in his favour: He was a police officer. And that meant prosecutors faced long odds.
In the end, they overcame those odds. Chauvin was found guilty on all counts Tuesday, becoming the rare police officer convicted of murder for killing someone while on duty.
That outcome, experts said, was due to an overwhelming case presented by prosecutors, who sought to fully sever Chauvin from policing, the job he held for nearly two decades.
And Chauvin's defence could not overcome the trial's centerpiece: video of the White police officer driving his knee into Floyd's neck as the Black man gasped for air.
"The defence was boxed in, in many ways, and had to make the case his conduct was reasonable," said Philip M Stinson, a criminologist at Bowling Green State University who studies arrests of police officers. "But the problem is, you can't rationally explain Derek Chauvin's conduct."
The jury's decision - convicting Chauvin of second-degree unintentional murder, third-degree murder and second-degree manslaughter after deliberating for about 10 hours - capped the most prominent policing trial in decades.
The case was gruelling, with prosecutors calling up a parade of tearful bystanders, disapproving police officers and blunt-speaking medical experts since testimony began three weeks ago.
But although the evidence and testimony against Chauvin seemed devastating to some observers, legal analysts and policing experts warned that such trials are never easy to win. Police officers who kill people while on duty are seldom charged with crimes, and when they are, convictions are sparse.
Police in the United States shoot and kill about 1,000 people a year, according to a Washington Post database.
Most of these people are armed and the shootings deemed justified. When police are charged in those cases, the officers are convicted in fewer than half the cases, often on lesser charges, including in cases with video that fuels public outrage.
Experts and lawyer who have worked on such cases attribute these outcomes to consistent factors: Police have considerable legal latitude to use force, including deadly force.
When accused of murder, they can point to their training, saying they followed it when using force. And, in court, judges and juries trust them.
Even the gripping video of Floyd pinned down that spurred a global outcry and was replayed in court would not necessarily be enough to sway a jury, Stinson said.
"We've seen with other cases where there has been damning video evidence [and] the prosecution has struggled to get a conviction," he said.
Chauvin's defence attempted to appeal to at least some of the factors that have benefited officers in other cases.
Eric Nelson, the former officer's defence attorney, said during his closing argument that in his encounter with Floyd, Chauvin was following his police training and acting as any "reasonable officer" would have in his position.
That defence comes from the Supreme Court's 1989 Graham v Connor decision, which says an officer's actions must be judged against what a reasonable officer would do in the same situation.
This argument has been crucial in many cases when police are charged over their use of force, experts said.
But the arguments that Chauvin followed his training and did what a "reasonable officer" might do were undercut by the multiple Minneapolis police officials, including Chief Medaria Arradondo, who said the former officer had violated police training and ethos, said Christopher Slobogin, a law professor at Vanderbilt University.
"The prosecution did a great job, because they put officer after officer on the stand to show that, actually, a reasonable cop would not have acted the way Chauvin did," Slobogin said. "That it was unreasonable to do what Chauvin did, and that cops are trained to do just the opposite under similar circumstances."
Still, lawyers and other experts said history has shown that at least some jurors might hesitate to convict police officers on the most serious charges.
These jurors, they say, recognize that policing can be dangerous and that officers might have to make split-second decisions in dangerous circumstances.
‘Not a prosecution of the police’
Some experts and lawyer thought Chauvin's strongest defence strategy heading into the trial might be to appeal to any jurors reluctant to convict police, seeking to sway their votes, deadlock the jury and force a mistrial. Prosecutors appeared to acknowledge this possibility in their closing remarks, recognizing that it might be difficult for some jurors to vote to convict a police officer.
"It may be hard for any of you to imagine a police officer doing something like this," prosecutor Steve Schleicher said during closing arguments.
"Imagining a police officer committing a crime might be the most difficult thing you have to set aside, because that's just not the way we think of police officers. We trust the police."
But, Schleicher said, "this is not a prosecution of the police." Instead, he said, what Chauvin did "was not policing."
That effort to separate Chauvin from police was "a wise choice" to appeal to any jurors who might be uneasy with some of the sharpest criticisms of police and calls to reform or defund them, said Daniel S Medwed, a law professor at North-eastern University.
"They didn't want to make it a trial about policing, but rather a trial about a police officer gone bad," Medwed said. "That was probably a very effective argument."
The defence, in turn, sought to portray the case as being about policing, saying, "'This was a tragic event but not one that exceeded the bounds of what a reasonable officer would do,'" Medwed said.
Legal experts said Chauvin's defence did present some potentially potent arguments, such as the contention that it was Floyd's drug use and existing health problems, not the officer's knee, that killed him.
This attempt to interrupt what is called the chain of causation - separating Chauvin's knee from Floyd's death - was cited by some experts as perhaps the defence's strongest case.
"There was ambiguity about causation," Slobogin said. "There was enough ambiguity there. The defence could've gotten its toe in the door in that issue. . . . The causation argument was really the defence's only hope."
But prosecutors "did a very good job presenting sufficient expert testimony to rebut the defence's argument," Slobogin said.
The defence faced other head winds, such as the intense public focus on the case and jurors' awareness that they could face criticism and that their communities might be gripped by unrest if people disapproved of how they voted, said Patrick Thomassey, a lawyer in Pittsburgh who has represented police officers charged with killings.
"There's tremendous amounts of public pressure on a jury," Thomassey said. "I'm not criticizing their verdict; they found what they found. But these kinds of cases, there's so much they have to think about, in terms of repercussions. . . . There's just so much public pressure to convict on a high-profile case like this."
Thomassey also said he was disturbed by the revelation during jury selection that the city had reached a $27 million settlement with Floyd's family, which he said might have suggested to some jurors that the city was confirming wrongdoing on the part of the officers.
"I know what happens in jury rooms," he said. "Whether Mr Chauvin was guilty or not, the most important part is that he gets a fair trial."
Experts said they expected Chauvin to appeal his conviction, and he also faces an ongoing federal civil rights investigation. The former officer also still faces sentencing in this case.
Medwed said that much of Chauvin's widely watched case boiled down to the evidence that everyone saw before he was charged last year.
"I think he had a shot," Medwed said of Chauvin. "It's just, the prosecution had a very strong case. And that video; to some extent, the video really sealed Chauvin's fate."
After Floyd died last year, police put out a statement saying that he "physically resisted officers" and then "appeared to be suffering medical distress."
The bystander video footage told a far different story, one that continued to reverberate in the courtroom where Chauvin was found guilty.