A trial judge failed to follow case law and court rules when he rejected a proposal to add third-degree murder charges against four former Minneapolis police officers charged in George Floyd's death, prosecutors argued in a court filing Monday.

Attorney General Keith Ellison's office filed the memorandum further explaining why the Court of Appeals should intervene and overturn the trial judge's ruling. Prosecutors are asking the Court of Appeals to apply its own interpretation of third-degree murder to the case instead of the interpretation by Hennepin County District Judge Peter Cahill, who rejected prosecutors' request to add the charges.

"The District Court's decision was erroneous and a clear abuse of discretion," wrote Assistant Attorney General Matthew Frank and Special Attorney for the State Neal Katyal. They said it's unfair "because it permits different courts to apply different rules in otherwise similar circumstances. And it threatens to undermine public faith in the judicial process and the rule of law."

Prosecutors want to reinstate a count of third-degree murder against Derek Chauvin and to add aiding and abetting third-degree murder for the first time against J. Alexander Kueng, Thomas Lane and Tou Thao.

Chauvin is charged with second-degree murder and manslaughter and is scheduled to be tried March 8. He had been charged with third-degree murder, but Cahill dismissed that count in October because the charge typically applies when a suspect's actions put multiple people at risk and are not targeted at a single person.

The issue resurfaced after the Court of Appeals issued a 2-1 decision Feb. 1 upholding a third-degree murder conviction against former Minneapolis officer Mohamed Noor in the 2017 fatal shooting of Justine Ruszczyk Damond. The Court of Appeals wrote that third-degree murder can apply when a suspect's actions apply to a specific person and don't put others at risk.

That prompted prosecutors to file a motion Feb. 4 asking Cahill to reinstate the charge against Chauvin and to add it against the other three defendants, who are charged with aiding and abetting second-degree murder and manslaughter. Cahill denied the motion, noting that the defendants' actions were directed at one person.

Cahill was wrong to apply his own reading of the statute instead of the Court of Appeals' standard, which is binding on both courts unless it's reversed by the Minnesota Supreme Court, prosecutors wrote.

The judge also misinterpreted case law in rejecting the prosecution's motion, they added.

According to the memorandum: The district court and Court of Appeals are bound by published opinions from the Court of Appeals, according to the Minnesota Rules of Civil Appellate Procedure.

Chauvin's attorney, Eric Nelson, previously argued in a court filing that the Court of Appeals decision is not yet precedent because of a window of time that allows Noor's attorneys to ask the state Supreme Court to review the ruling. Nelson has argued that the Court of Appeals should dismiss the prosecution's request for intervention.

Noor's attorney, Thomas Plunkett, has said he will ask for the state Supreme Court's review. Plunkett also represents Kueng. Prosecutors said the Court of Appeals' ruling in Noor's case can apply despite the possibility of state Supreme Court intervention.

The third-degree murder statute is not written to apply only when a suspect's actions put others at risk and when there is no specific target, prosecutors wrote, adding that previous state Supreme Court rulings support their stance.

In Floyd's case, the defendants were arresting him for allegedly using a fake $20 bill when they pinned him stomach-down in the street, with Chauvin kneeling on his neck for more than nine minutes.

Third-degree murder applies when someone "without intent to effect the death of any person, causes the death of another by perpetrating an act eminently dangerous to others and evincing a depraved mind, without regard for human life," according to state statute.

It is commonly used to charge drug dealers in overdose deaths; veteran attorneys have said it would apply, for instance, to someone shooting indiscriminately into a moving train.

Prosecutors argued that it would critically affect their cases if they are unable to add third-degree murder.

Kueng, Lane and Thao are scheduled to be tried together starting Aug. 23.

Chao Xiong • 612-270-4708

Twitter: @ChaoStrib