A federal appeals panel last week upheld a judge's ruling that a lawsuit filed against a Minneapolis police officer can proceed, writing that the officer's incorrect assumption of the source of injuries he incurred during an arrest could have been cleared up with "any minimal amount of investigation."

The three-judge panel of the U.S. Eighth Circuit Court of Appeals found that Officer Robert Heiple had no grounds to arrest Catrina Johnson when he wrongly assumed that she had kicked him — when, in fact, he had suffered a rupture or a sprain. Attorneys for Heiple and the City of Minneapolis argued that he was reacting to a volatile situation.

Johnson's attorney, Peter Nickitas, praised the panel's decision, which was delivered Friday. "It's a case that says simply the officer should've known it's been against the law for nearly 20 years to arrest someone without a warrant when he hasn't actually seen anything," he said, pointing to a 1999 precedent. In that case, the Eighth Circuit found that a South Dakota police officer's actions were not protected when he "ignored plainly exculpatory evidence" and arrested a boutique employee without probable cause.

Police didn't respond Monday to a request for comment.

Johnson sued Heiple and the city in 2015 over an incident two years before in which she called police to report that her son had assaulted her. Court filings show that Heiple and another officer had just handcuffed Johnson's son when Heiple felt sharp pain like an "explosion" in his right calf. Turning back toward Johnson, who was standing nearby in her bathrobe and slippers, he asked her twice whether she had kicked him. Even though she and a witness denied it, Heiple arrested her, according court filings.

"In the end, there is one factor which cuts decisively against arguable probable cause: Officer Heiple did not observe Johnson committing a criminal act — and nobody told him that Johnson did either," the unanimous decision read.

Johnson was booked into jail on suspicion of obstructing the legal process and fourth-degree assault. She was released several days later without being charged.

Her suit seeks $75,000 in damages.

The 16-page ruling affirms a decision in April by U.S. District Judge John Tunheim, who wrote that while Heiple may have believed in the moment that Johnson kicked him, "any minimal amount of investigation" would have revealed that she had not.

"In addition, nothing in the record indicates that Johnson — a 5-foot, 4-inch disabled woman weighing about 140 pounds and wearing a slip and soft shoes — had her cane during the incident, making Johnson's ability to kick Officer Heiple with sufficient force as to cause 'explosive pain' improbable," Tunheim wrote.

The city attorney's office said that it was reviewing the decision without offering further comment.

Heipel's lawyers argued that his actions were protected by qualified immunity, a legal doctrine that protects police from being sued for actions on the job, because the officer was concerned with "Johnson's emotional state and her undetermined position behind" him.