A prosecutor in the assault trial of Minneapolis police officer Efrem Hamilton argued Monday that her case was hampered by a “blue wall of silence” after three of the officer’s colleagues changed or clarified their testimony on the witness stand.

Assistant Hennepin County attorney Tara Ferguson Lopez appealed to District Judge Fred Karasov following the testimony of three of Hamilton’s fellow officers that she said differed in some details from statements they had given her office or documented in a police report.

Hamilton faces charges of second-degree assault and two counts of intentional discharge of a firearm, all felonies.

“The officers that previously testified — there were some very obvious and notable changes in what they indicated in their reports and in prior discussions, and what they testified about today,” she told Karasov, later pointing out that some officers might feel indebted to Hamilton’s defense attorney Fred Bruno, who regularly represents cops in court. “So I do think it’s an issue in this case.”

Ferguson Lopez said the officers — homicide detective Sgt. James Jensen and patrolmen Craig Williams and Chad Martin — “aside from being very hesitant and tentative witnesses, changed their testimony and how they provided that information.” Ferguson Lopez stopped short of saying that the officers had tailored their testimony of the defense.

Of particular concern to Ferguson Lopez, who called the three officers as witnesses, were apparent discrepancies in statements they made on the night of shooting.

“Would it help to refresh your recollection of whether you smelled anything by taking a look at your report, officer?” she asked Williams after his response about whether he smelled gunpowder as he walked toward Hamilton’s SUV.

Williams testified that he and Martin, his partner, happened to be in the area when the shooting occurred, describing the immediate aftermath as “calm,” shattered moments later by was described as the sound of a tire popping.

Unsatisfied, Ferguson Lopez walked over to the stand to show him a copy of his report, before asking flatly: “Does that report refresh your recollection?”

Hamilton was working an off-duty job when he responded to the call about a large brawl-turned-shooting near Target Field on Nov. 20, 2016. Dispatchers aired a description of the suspect vehicle as a “gray sedan.”

Hamilton fired a single shot into a gray BMW, moments after it slammed into his police SUV while trying to flee the shooting, driving backward in the wrong direction on 3rd Avenue. No one was injured, but prosecutors in a rare move charged the officer, arguing that he’d acted recklessly.

The defense has argued that Hamilton, believing that the BMW fit the description of the suspect’s vehicle, was justified in firing his weapon.

Ferguson Lopez argued that Jensen flip-flopped on details about whether he heard the BMW’s engine revving after it slammed into Hamilton’s SUV.

“Before today, you never indicated that the revving was coming from the BMW,” said Ferguson Lopez.

“I haven’t changed it — I reviewed it,” Jensen said.

At one point, Bruno raised an objection, saying that the prosecutor was being “argumentative” with her own witness.

During a jury recess, Karasov said that her concerns about witnesses’ bias were “appropriate.”

“[Jensen] would have a reason arguably to help Mr. Hamilton,” the judge said. “I allowed you to explore that bias, and I think you did establish that bias.”

Both attorneys have repeatedly declined to comment, citing a gag order issued by the court.

The trial resumes Tuesday morning.

Another state witness, Mike Quinn, testified that most officers adhere to the “blue wall of silence,” an unwritten rule against giving incriminating information against a fellow officer.

Officers who break the code, Quinn said, are often ostracized.

In his cross-examination of Quinn, Bruno questioned his credibility as an expert on police use of force and culture by pointing out that the former Minneapolis police sergeant had last worked the streets in the early 1990s.