Derek Chauvin's attorney asked the Minnesota Court of Appeals on Wednesday to throw out the former Minneapolis police officer's convictions in the murder of George Floyd, the latest and what could be the final courtroom proceeding in a case that spans nearly three years.

When Chauvin knelt on the unarmed Black man's neck for more than nine minutes in May 2020, the world responded to a bystander's video of the killing with outrage, riots and protests by the thousands. But Chauvin's appellate attorney William Mohrman said that pretrial publicity — the unrest and subsequent movement for police reform — made a fair trial impossible.

"The main remedy my client is looking for is a new trial," Mohrman told the three-judge panel.

A Hennepin County District Court jury convicted Chauvin of second-degree unintentional murder, third-degree murder and second-degree manslaughter in April 2021, and he was sentenced to 22½ years in prison that June. He later pleaded guilty in federal court to charges of violating Floyd's civil rights and received a concurrent 21-year sentence that he cannot appeal.

Mohrman asked the appeals court to either reverse the state convictions or grant a new trial outside Hennepin County.

"The primary issue on this appeal is whether a criminal defendant can get a fair trial consistent with constitutional requirements in a courthouse that's surrounded by concrete block, barbed wire, two armored personnel carriers and a squad of National Guard troops all ... there for one purpose: in the event that the jury acquits the defendant," he said.

Chauvin is being held at a medium-security federal prison in Tucson, Ariz., and even if he were to win his appeal, he still must serve out his federal sentence.

A decision on his appeal is expected within 90 days.

Mohrman has represented controversial landlords accused of substandard conditions and won a major victory several years ago when the Eighth U.S. Circuit Court of Appeals struck down a 101-year-old state law that made it a crime to make false political statements about a ballot question.

In Chauvin's appeal, he argued that prosecutors failed to prove sufficient probable cause, among other alleged legal errors outlined in his brief, and that the jury was tainted since the killing and trial all played out in Minneapolis.

Calling the pretrial publicity pervasive, Mohrman also pointed to the "physical pressure on the courthouse" and concerns jurors had for their safety. He said the unrest that followed Floyd's killing made this case unique. Leading up to Chauvin's verdict, he said, the city braced for more riots in the event of an acquittal.

Media coverage was more extensive than any other trial in Minnesota's history, he said, arguing that the court abused its discretion by denying a change of venue.

"The jurors that sat on this jury had a stake in the outcome of the case because they lived here where the riots occurred," Mohrman said. "If this case gets moved out state, the likelihood of having riots in the community where the jurors are living, I believe will be a zero."

Chauvin's trial was the first in Minnesota to be livestreamed worldwide. Minnesota is one of the few states that still bans cameras in the courtroom, with rare exceptions. District Judge Peter Cahill allowed Chauvin's trial to be livestreamed because of the pandemic and high public interest.

Wednesday's appeal hearing was also livestreamed. Each party had 15 minutes to make oral arguments. A significant amount of that time was focused on the venue issue and Mohrman's accusation that one juror lied.

Brandon Mitchell, a Black man who was then 31, was one of the 12 jurors who convicted Chauvin and the first to go public. After the verdict, an August 2020 photo of him at an event in Washington, D.C., commemorating Martin Luther King Jr.'s "I Have a Dream" speech drew criticism — and potential grounds for an appeal.

The photo showed Mitchell wearing a T-shirt with a picture of King surrounded by the words, "GET YOUR KNEE OFF OUR NECKS" and "BLM" (Black Lives Matter).

"I'd never been to [Washington] D.C.," Mitchell told the Star Tribune after the post surfaced. "The opportunity to go to D.C., the opportunity to be around thousands and thousands of Black people; I just thought it was a good opportunity to be a part of something."

Mohrman contended that Mitchell lied by saying he never participated in a protest in Minneapolis. But Judge Peter M. Reyes Jr. told him that he doesn't believe Mitchell was lying because the march he attended was outside Minneapolis. Reyes said that even Chauvin and his attorneys seemed to acknowledge the difference when Mitchell was seated as a juror.

Reyes said he had a hard time understanding Mohrman's argument regarding the juror, whom he said seemed forthright about BLM and "that Black and racially and ethnically diverse people were not necessarily treated fairly by the police."

Neal Katyal, who was acting U.S. solicitor general during the Obama administration and served as one of the special prosecutors in Chauvin's murder trial, said in his oral argument that Chauvin's attorneys asked Mitchell seven times if he could render a fair verdict and they chose to seat him on the jury.

"[Mitchell] wasn't trying to hide the ball or anything like that. He was very clear about his views of police brutality and racism," Katyal said.

On the issue of venue, he said Cahill made clear that even if the trial were in a smaller venue, the security would stand out and there would be the same fears of civil unrest.

Katyal said Chauvin's appeal arguments do not come close to reversing his convictions.

"It was one of the most transparent and thorough trials in our nation's history," he said.

Jurors heard from 44 witnesses, including bystanders and experts, and viewed extensive video recordings, Katyal said. They learned about Chauvin's training and how to avoid prone restraints because of positional asphyxia, he said, "which is the very thing that killed Floyd."