For weeks, arguments in the murder case against a Minnesota state trooper have hinged on what an independent use-of-force expert concluded about the officer's actions — and why Hennepin County Attorney Mary Moriarty chose to disregard those findings.

Defense attorneys for trooper Ryan Londregan insist that Moriarty's handpicked expert, Jeffrey Noble, told prosecutors Londregan "committed no crime" when he shot and killed motorist Ricky Cobb II during a traffic stop last summer.

But Noble never made such a legal determination, according to a document in the case.

A two-page report summarizing a virtual meeting between Noble and Moriarty's senior staff on Oct. 13, 2023, reveals a more nuanced analysis from Noble.

He initially opined that a reasonable officer would have acted like Londregan did to protect his partner, who was being dragged as Cobb's car lurched forward. "The danger was not hypothetical," Noble observed.

However, the retired Irvine, Calif., deputy police chief hired by Moriarty's office to consult during the charging review process asked for more time to review the case. He had not yet made his opinions formal in writing, according to the memo.

"Mr. Noble refrained from offering an ultimate opinion during the meeting on whether a reasonable officer would have believed that deadly force was necessary to prevent death or great bodily harm when Trooper Londregan shot Mr. Cobb," the memo says.

The Star Tribune obtained a copy of the memo after Judge Tamara Garcia allowed pretrial exhibits to be made public, per a request from KARE 11, who first reported the memo.

The memo, prepared by Moriarty's staff, says that Noble's primary focus would be whether Londregan's use of deadly force was reasonable in the moment, and whether his actions prior to the shooting were "reckless such that they created an unreasonable danger" resulting in deadly force.

Noble offered to discuss some "preliminary impressions" with Moriarty and six members of her senior staff based on his examination of some investigative materials, such as videos, photos and State Patrol policy and training guides. He did not yet have transcripts from the investigative grand jury, because Moriarty convened it in December.

She announced that an expert opinion was critical to making her charging decision. But she stopped working with Noble and charged Londregan with second-degree murder, manslaughter and first-degree assault. She said her office was "able to determine charges were appropriate without" the use of an expert.

Here are some takeaways from the memo.

On the use of deadly force:

Noble said interpreting the reasonableness of Londregan's actions would be complicated because the trooper refused to provide a statement. So he doesn't know for certain why he fired at Cobb.

If the trooper fired to prevent Cobb from fleeing, Noble would deem the use of deadly force to be unreasonable. But if he fired out of fear for his partner Trooper Brett Seide's safety, "a reasonable officer in Trooper Londregan's position would have perceived that Trooper Seide was in danger of great bodily harm, specifically from being dragged by the vehicle as is continued to accelerate."

He was asked about potential alternatives, such as doing nothing or encouraging Seide to exit the car, and whether the use of deadly force was "necessary'' at the time it was used. Noble "acknowledged that the word 'necessary' is complicated and tricky, and it is unclear what state legislatures mean when they include it in their use-of-deadly-force statutes."

The summary notes say Noble "could not offer an opinion on what 'necessary' means" under the state's new statute.

On troopers' danger:

Noble told prosecutors that he thought it was a "bad idea" for Seide to reach into the vehicle. Yet, even if Seide's actions were unreasonable, that does not necessarily make Londregan's use of deadly force unreasonable.

"Trooper Londregan still was authorized to reasonably respond to the danger to Trooper Seide," Noble said, according to the memo.

"Mr. Noble offered that Trooper Londregan's decision to shoot so close to his partner was 'not the best decision,' but, since he did not injure Trooper Seide, that is 'not an important issue in the case.'"

Reactions to memo:

Even before the report became public, it escalated tensions between the defense and prosecutors, with both parties seizing on various parts of the document.

Londregan's supporters launched an aggressive media campaign asserting that Moriarty's office fired Noble because his opinion did not support their theory that the trooper acted criminally. Moriarty's office countered that defense attorneys "cherry picked" quotes from the memo and excluded "critical facts where the expert acknowledged information he would need to fully analyze the case."

Subsequent filings — including one alleging that the State Patrol's own use-of-force trainer said Londregan didn't violate policy — raised the pressure.

Gov. Tim Walz has publicly questioned Moriarty's handling of the case and six of Minnesota's eight-member U.S. House delegation have called for Walz to reassign the case, which is within his authority.

Cobb's family released a statement last week, telling Walz "to put justice before politics and let County Attorney Moriarty bring this prosecution without any further interference."

The racial justice organization Color Of Change accused the Minnesota Police and Peace Officers Association, a trade group whose legal defense fund is paying Londregan's attorneys, of misinforming the public and lawmakers. "[MPPOA] sold these lies to Gov. Walz, and now Moriarty is facing the repercussions of this misinformation," said Michael Collins, senior director of state and local government affairs for Color of Change.

Londregan's attorney, Chris Madel, told the Star Tribune in a text message Friday that Noble's statements satisfied the use-of-force statute by acknowledging that his conduct was "reasonable" — even if he never actually used the word "justified" to describe Londregan's actions.

"You don't have to use the word 'justified' to come to same conclusion," Madel said.

That is typically left for a jury to decide.

Read the memo:

[Can't see the document? Click here.]