Charleston – A South Carolina judge declared a mistrial on Monday after a jury deadlocked in the murder trial of a white former police officer charged in the shooting death of an unarmed black motorist.A panel of one black and 11 white jurors – who had seemed close to a verdict to convict on Friday, with apparently only one holdout – said on Monday they were unable to reach a unanimous decision after deliberating more than 22 hours over four days."We as a jury regret to inform the court that despite the best efforts of all parties we are unable to come to a unanimous decision," said Circuit Judge Clifton Newman, reading a note from the jury before declaring a mistrial.Former patrolman Michael Slager was charged with murder in the April 4, 2015, shooting death of 50-year-old Walter Scott. The judge had said the jury could also consider a lesser charge of voluntary manslaughter.Outside the courtroom, Scott's mother and brother said justice will eventually prevail."I'm not sad, because I know justice will be served," Judy Scott said.Asked whether he could forgive Slager, Anthony Scott said he could eventually "find the peace" to forgive the ex-officer but not before justice is served."He gets to spend Christmas with his family," he said of Slager.Shot in the back five timesCellphone video taken by a bystander that showed Scott being shot in the back five times was shown widely in the media and on the Internet and shocked the country, inflaming the national debate about how black people are treated by law enforcement officers.After the video went public, Slager was fired by the police department and charged with murder. Scott's family called for peace in the North Charleston community. Their calls for calm are believed to have helped prevent the kind of violence that erupted elsewhere when black men were killed in encounters with law enforcement.It's the second time in recent weeks a jury has deadlocked in an officer-involved shooting. A mistrial was declared on November 12 when a jury in Cincinnati couldn't reach a verdict in the case of a former campus police officer who was also charged with shooting a black motorist.The video in the Scott slaying renewed debate about how black people are treated by white law officers. There have been similar debates over race and policing in places from New York to Ferguson, Missouri, and from Tulsa, Oklahoma, to North Carolina.Slager's wife, Jamie, cried after the jurors were dismissed and briefly put her head on the bench in front of her. She said "thank you for everything" to the defence lawyers as they left the courtroom. She did not respond when reporters asked if she wanted to comment.One female juror wiped away tears with her hands and a tissue as the attorneys addressed them and thanked them for their hours of work.There were no outbursts in the courtroom. Slager's lawyer, Andy Savage, did not comment.Scott's family again called for peaceful protests.New trial"We're not going to tear up this city," Anthony Scott said. "We're not happy. But we're not sad."Solicitor Scarlett Wilson praised Scott's family for their patience and understanding."They have not received the credit they deserve in their calm leadership for the community," she said in a statement. "The Scotts have been a sterling example of dignity and grace in extraordinary circumstances."Slager also faces trial next year in federal court on charges of depriving Scott of his civil rights.Governor Nikki Haley said that she understood there will be "a new trial where the Scott family and all of South Carolina will hopefully receive the closure that a verdict brings. Justice is not always immediate, but we must all have faith that it will be served; I certainly do."While Slager is white and Scott was black, the video, not the races of the men, dominated the trial.Scott was pulled over in North Charleston for having a broken taillight on his 1990 Mercedes and then fled the car, running into a vacant lot. Family members have said he may have run because he was worried about going to jail because he was $18 000 behind on child support.The prosecution argued that the 35-year-old Slager let his sense of authority get the better of him.The defence maintained that the two men wrestled on the ground, that Scott got control of Slager's stun gun and then pointed the weapon at the officer before the shooting. The defence also contended there was no way the officer could tell if Scott was unarmed.Last year, the city of North Charleston reached a $6.5m civil settlement with Scott's family. In the wake of the shooting, the city also asked that the US Justice Department conduct a review of its police department policies with an eye toward how the department can improve its relationship with residents.