MINNEAPOLIS (AFP) - Nine months after Mr George Floyd's death laid bare the racial wounds in the United States, the white policeman charged with murdering the 46-year-old Black man is going on trial.

Jury selection begins in Minneapolis on Monday (March 8) in the case against Derek Chauvin, who was filmed with his knee on Mr Floyd's neck for nearly nine minutes as the handcuffed man struggled to breathe.

The shocking footage of Mr Floyd's May 25 death sparked a wave of "Black Lives Matter" protests against police brutality and racial injustice across the US and in capitals around the world.

Chauvin's case promises to be extraordinary in many respects: it will feature star attorneys, be held under tight security and broadcast live.

The Minnesota Attorney-General's Office brought in Mr Neal Katyal, a former acting solicitor-general who has argued cases before the Supreme Court, to help with the prosecution.

Mr Katyal described Chauvin's trial as a "landmark criminal case, one of the most important in our nation's history".

Mr Ashley Heiberger, a former police officer who now works as an adviser on police practices, said "the fact that a police officer has been charged criminally for an abusive use of force, that in and of itself is an outlier".

He said: "It's even rarer for them to be convicted. There is a tendency for jurors to want to give the police officer the benefit of every doubt."

But the circumstances surrounding 44-year-old Chauvin's case are so troubling that "to the best of my knowledge, no police officers or police organisations came out and defended his action", he added.

Three other police officers involved in Mr Floyd's arrest - Alexander Kueng, Thomas Lane and Tou Thao - face lesser charges and will be tried separately.

All four officers were fired by the Minneapolis Police Department.

Mr Floyd's arrest was prompted by accusations that he had tried to pass off a US$20 (S$27) bill in a nearby store.

Chauvin, a 19-year veteran of the force, was released from prison on bail and is expected to plead not guilty to murder and manslaughter charges.

"Mr Chauvin acted according to MPD policy, his training and within his duties as a licensed peace officer of the State of Minnesota," his lawyer Eric Nelson said, referring to Minneapolis Police Department. "He did exactly as he was trained to do."

According to Mr Nelson, Mr Floyd died of an overdose of fentanyl.

An autopsy did find traces of the drug in Mr Floyd's system but said the cause of death was "neck compression".

Mr Ben Crump, a lawyer representing the Floyd family, said on Saturday he was expecting the defence team to attack Mr Floyd's character.

"They're going to call George everything but a child of God, and try to make you forget what you see on that video," he said.

It will take a unanimous verdict by the 12 members of the jury to put Chauvin behind bars for what could potentially be a long prison sentence.

Just a single juror not voting for conviction could result in a hung jury and give rise to another wave of anti-racism demonstrations.

The authorities have mobilised thousands of police officers and members of the National Guard to provide security during the trial.

The Hennepin County courthouse where it is taking place currently resembles an armed camp surrounded by concrete barriers and barbed wire fencing.

The trial is set to begin on Monday at 8am local time (10pm Singapore time) with jury selection - a delicate process considering the widespread publicity surrounding the case.

Prospective jurors have been presented with a 15-page questionnaire.

"How favourable or unfavourable are you about Black Lives Matter?" is one of the questions. "Have you ever watched video of George Floyd's death?" is another. "If yes, how many times?"

Potential jurors are also being asked: "Did you, or someone close to you, participate in any of the demonstrations or marches against police brutality?"

Prosecutors are expected to present testimony by a Black woman who claims that Chauvin used excessive force against her in 2017 and the teenager who filmed Mr Floyd's death is also expected to be called to the witness stand.

Opening arguments are scheduled to begin on March 29 and a verdict is not expected until the end of April.