A jury has been selected in the federal trial of three Minneapolis police officers charged over the killing of George Floyd.

Eighteen jurors were chosen after questioning by the judge on Thursday, 12 who will deliberate and six alternates.

J. Kueng, Thomas Lane and Tou Thao are broadly charged with depriving Mr Floyd of his civil rights while acting under government authority.

Separately, they are charged in state court with aiding and abetting both murder and manslaughter as Derek Chauvin used his knee to pin Mr Floyd to the street.

George Floyd case
Minneapolis police officers Thomas Lane, left and J. Alexander Kueng, right, take George Floyd to a police vehicle in Minneapolis (Court TV/AP)

US district judge Paul Magnuson stressed repeatedly to jurors that fellow officer Chauvin’s conviction on state murder charges and guilty plea to a federal civil rights violation should not influence the proceedings.

Legal experts say the federal trial will be more complicated than the state trial, scheduled for June 13, because prosecutors in this case have the difficult task of proving the officers wilfully violated Mr Floyd’s constitutional rights – unreasonably seizing him and depriving him of liberty without due process.

Phil Turner, a former federal prosecutor said, said prosecutors must show that officers should have done something to stop Chauvin, rather than show they did something directly to Mr Floyd.

The videotaped killing of Mr Floyd triggered worldwide protests, violence and a re-examination of racism and policing.

Among the jurors excused was a man who said he has a problem watching the video of Mr Floyd’s arrest, and decided to stop watching it about six months ago.

George Floyd case
Minneapolis police officers from left, Tou Thao, Derek Chauvin, J. Alexander Kueng and Thomas Lane are seen attempting to take George Floyd into custody (Court TV/AP)

Mr Magnuson spoke about the magnitude of the case, telling jurors they must be able to set aside anything they might have learned during Chauvin’s state trial, in which he was convicted of murder and manslaughter, and decide this case based upon its own evidence.

He said the trial is expected to last four weeks. He also acknowledged the media attention on the case, saying: “I’m sure all of you know something about what happened to George Floyd.”

Mr Floyd, 46, a black man, died on May 25, 2020, after Chauvin pinned him to the ground with his knee his neck for nine and a half minutes, while he was face down, handcuffed and gasping for air.

Kueng knelt on Mr Floyd’s back and Lane held down his legs. Thao kept bystanders from intervening.

Chauvin was sentenced to 22 and a half years in prison on the state charges. In December, he pleaded guilty at a federal count to violating Mr Floyd’s rights.

Kueng, Lane and Thao are all charged with wilfully depriving Mr Floyd of the right to be free from an officer’s deliberate indifference to his medical needs.

The indictment says the three men saw Mr Floyd clearly needed medical care and failed to aid him.

Thao and Kueng are also charged with a second count alleging they wilfully violated Mr Floyd’s right to be free from unreasonable seizure by not stopping Chauvin as he knelt on his neck.

It is not clear why Lane is not mentioned in that count, but evidence shows he asked twice whether Mr Floyd should be rolled on his side.

Both counts allege the officers’ actions resulted in Mr Floyd’s death.