A prosecutor has told the manslaughter trial of a Minnesota police officer who killed Daunte Wright that Kim Potter violated her training and “betrayed a 20-year-old kid”.

Prosecutor Erin Eldridge began her opening statement by telling jurors that a police officer’s fundamental duty is to protect the sanctity of life.

She said officers promise to safeguard lives, preserve and protect, and maintain calm.

“We trust them to know wrong from right, and left from right,” Ms Eldridge said. “This case is about an officer who knew not to get it dead wrong, but she failed to get it right.”

Once Potter’s lawyers begin their defence, they are expected to claim that Wright made an innocent mistake by pulling her handgun instead of her Taser when she shot Wright in April as he tried to drive away from a traffic stop.

Wright’s Taser was holstered on her left side, and her handgun on her right. Prosecutors argue that she was trained explicitly about the danger of avoiding deadly mix-ups.

Potter is white and Wright was black. The shooting led to protests in the Minneapolis suburb of Brooklyn Center for days just as former Minneapolis Officer Derek Chauvin was on trial over George Floyd’s death.

It took almost a week to seat a jury that turned out to be mostly white.

Potter, 49, is charged with first-degree and second-degree manslaughter over Wright’s April 11 death.

The officer, who resigned two days after the shooting, has said she meant to use her Taser on the 20-year-old after he sought to drive away from a traffic stop as officers tried to arrest him, but that she grabbed her handgun instead.

Potter was training a new officer when they pulled Mr Wright over for having expired license plate tags and an air freshener hanging from the rear view mirror, according to a criminal complaint.

When they found that Mr Wright had an outstanding arrest warrant, they tried to arrest him but he got back into his car instead of cooperating. Potter’s body-camera video recorded her shouting “Taser, Taser, Taser” and “I’ll taser you” before she fired once with her handgun.

Ms Eldridge played extended body-camera video from the shooting, including the moments right after Potter shot Wright.

Her camera recorded her saying ”(expletive) I just shot him” and “I grabbed the wrong (expletive) gun”.

After his car rolled away, it shows Potter sink to the curb and sit down, further exclaiming “Oh my God.”

Defence attorneys argued in pretrial filings that her immediate reaction bolsters their argument that the shooting was a tragic accident.

But defence attorneys also have asserted that Potter was within her rights to use deadly force if she had consciously chosen to do so because Wright’s actions endangered other officers at the scene.

“She believed the use of a Taser was appropriate when she saw Mr. Wright’s abject denial of his lawful arrest coupled with his attempted flight,” defence attorney Paul Engh wrote in a pretrial filing seeking to dismiss one of the charges. “She could have shot him.”