Prosecutors in the murder trial of former Minneapolis police officer Mohamed Noor are determined to put his onetime partner on the stand, despite raising questions about his ability to accurately testify about the night Justine Ruszczyk Damond was shot.

As the prosecution's anticipated star witness, Matthew Harrity was the only other person there the night Noor shot and killed Damond in July 2017 after the two officers responded to her 911 call about a possible sexual assault behind her home. But both his recollection and cooperation have been shaky, prosecutors have contended. His version of what happened that night has changed, they said, and he has declined to make himself available for trial preparation.

Compounding the complications, Assistant Hennepin County Attorney Patrick Lofton told jurors in opening statements last week that the Minnesota Bureau of Criminal Apprehension (BCA) — the agency tasked with investigating the shooting — repeatedly fell short, initially failing to test key evidence and interview certain witnesses.

"They made some assumptions and they tried to fill in gaps with things that they did not understand," Lofton said of the investigation.

As the internationally watched trial enters its third week Monday, prosecutors are placed in the unusual position of relying on the testimony of officers and investigators whose credibility they at times question.

In a pretrial filing, prosecutors wrote that jurors should be instructed to "question the credibility of any officer's testimony if he or she demonstrates an unwillingness to give full or truthful testimony because of a bias toward police. ... Similarly, the behaviors and statements of particular officers and investigators at the crime scene and during the investigation that demonstrate bias are relevant to show how and why certain evidence was or was not acquired or preserved."

Regardless, 10 of the 13 witnesses called so far at trial have been Minneapolis police officers or BCA specialists. Noor has maintained his silence since Damond's death, declining to speak with the BCA or to a grand jury investigating the shooting, and it is unclear whether he will testify in his own defense.

Some legal experts said that it makes little sense for prosecutors to cast doubt on the credibility of Harrity, whose testimony will be crucial to both sides' arguments. If anything, the state may be trying to lay a foundation for a later effort to convince the jurors that an officer was being untruthful in his or her testimony, experts say. But, the tactic could backfire, said veteran defense attorney Earl Gray.

"If they include the BCA and the Minneapolis Police Department, who are they going to have to investigate their cases?" said Gray, who successfully defended former St. Anthony police officer Jeronimo Yanez in the shooting death of Philando Castile. "It's my experience working with any of these law enforcement agencies: They have a long memory."

Tensions high

Tensions between the Hennepin County Attorney's Office and the union that represents the Minneapolis Police Department's rank-and-file officers have run high since the trial of Efrem Hamilton, a police officer who was acquitted last year of firing at a car full of teenagers whom he mistook for suspects in a shooting. Allegations of dishonesty surfaced during that trial, when a prosecutor from Freeman's office openly questioned whether a veteran homicide detective gave differing accounts of what happened, prompting a defense objection that the prosecutor was being "argumentative" with her own witness.

The feud intensified last year when Freeman's office began subpoenaing dozens of officers involved in the Damond shooting, claiming that they refused repeated requests to provide statements, acting on the advice of union lawyers. Some officers, including Chief Medaria Arradondo, spoke with prosecutors voluntarily, but others were threatened with criminal contempt unless they testified, the union said.

The standoff forced Freeman to convene a grand jury to compel the officers to testify, the county attorney said later.

Chuck Laszewski, a spokesman for Freeman's office, declined to comment, as did Harrity's attorney, Fred Bruno.

Noor's defense team asked Judge Kathryn Quaintance to bar prosecutors from mentioning the existence of "a blue wall of silence," regarding officers' interactions with their union during the investigation. Quaintance agreed, ruling that the state must give evidence backing their claim.

Police union President Lt. Bob Kroll scoffed at the suggestion that officers had been less than straightforward with prosecutors.

"That's an easy sweeping statement to make and without some concrete hard evidence, which they won't find in this case," said Kroll.

Kroll said he sent out an e-mail to officers urging to prepare themselves for hostile questioning if called to testify.

Paraphrasing the e-mail, Kroll said he told officers to: "Choose your wording carefully; better to be prepared and see what the line of questioning is going to be on this, then to be blindsided."

Body camera footage played during testimony last week repeatedly showed officers switching the devices off when speaking with colleagues in the aftermath of the shooting. Additionally, they offered Noor and Harrity unsolicited advice to keep quiet, contacted union officials on their behalf and turned a squad camera off before Noor was seated inside the vehicle.

Hennepin County public defender Mary Moriarty has said that her office keeps a running list of officers they believe are caught lying or falsifying evidence, but she is unaware of any officers accused of covering up for a colleague's misdeeds while testifying. But, she said, discrepancies between a person's trial testimony and his or her pretrial statements aren't necessarily proof of a coverup.

"It's common for witnesses in jury trials to testify about something that's different from their initial statement, and that includes police officers," Moriarty said.

Joshua Page, an associate professor of sociology and law at the University of Minnesota, said that the dangerous realities of police work tends to breed an insular culture that resists change and outside influence.

"By no means does this say that police will be silent in the face of criticism of colleagues, but the job itself and the culture it develops, produces a real close-knit social bond and this feeling that people on the outside don't really understand it — what it means to be police," he said, while adding silence is codified in some police contracts that allow officers to consult with union representatives before giving a formal statement following a police-involved shooting.

Paul Applebaum, a St. Paul-based attorney who has represented clients who have sued police officers for alleged misconduct, said he wasn't surprised that prosecutors in the Noor case had met some resistance from other officers.

"They're having to deal with that unified front that civil rights lawyers have had to deal with since the dawn of time," he said.