A few minutes before 1 a.m. on an unseasonably warm November morning four years ago, Minneapolis police officer Michael Griffin phoned his partner for backup.

Griffin, who was off duty, was being confronted by a group of men with whom he'd exchanged words at a North Loop bar and feared for his safety, he told officer William Gregory. Gregory, who was working as an off-duty security guard at a nearby Cub Foods, raced to the scene in his squad car.

Federal prosecutors have a different reading of the events of that night, Nov. 5, 2011, contending that Griffin — not the other men — was the antagonist in the encounter.

Details of the fight between Griffin and the four men — Jeremy Axel, Matthew Mitchell, Keyon Cooley and another man at the Loop Bar — were debated Friday, on the fourth day of testimony in the officer's trial on deprivation of civil rights and perjury charges in federal court in St. Paul.

On Friday, Mitchell, a former arena football player who stands 6-foot-3 and 240 pounds, walked jurors step-by-step through what started as a guys' night out and ended with a bloody confrontation in the street. He echoed the prosecution's charge that Griffin grabbed Cooley outside the bar, "flipped him to the ground … kicked [Mitchell] in the chest and punched [Axel] in the head from behind, rendering [him] unconscious." Afterward, prosecutors say, Griffin used his status as a police officer to stymie an investigation, repeatedly lying on police reports and giving false testimony.

The defense argued that Mitchell's testimony conflicted with statements he made to investigators.

There is no dispute that Griffin got into a physical altercation with the group on that night, first outside and then around the corner from the Loop Bar. But witnesses say the men started fighting after an argument broke out inside the bar when the men asked Griffin to move so that Axel could join his friends.

Prosecutors said that Griffin, who had come downtown after an off-duty shift as a security guard at a North Side gas station, followed the group outside, making threats to call "his boys to come [expletive] you up."

Axel and his friends previously testified that they were not aware that Griffin was a police officer. Mitchell testified that Griffin kicked him in the chest, sending him staggering back, and also punched Axel.

Mitchell said in a sworn statement sometime after the attack that Griffin had "picked up [Axel's] limp body with one hand and as he was hanging reared back and roundhouse kicked him," according to a transcript that was read in court.

The four men sued Griffin and Gregory in federal court two years later and a jury deemed that the latter used excessive force against Axel, but not Mitchell or Cooley, awarding Axel $125,000. A U.S. district judge ordered the city to pay another $145,000 in attorney's fees.

Griffin's attorney, Robert Richman, contended that the mixed-race group had singled out Griffin, who is black, not only because he was a cop, but also because of his race.

"So when you said, 'I'm gonna call my boys to (expletive) you up,' did you think that some Vice Lords were going to walk through that door?" Richman asked Mitchell, saying that his earlier testimony suggested that he mistook Griffin for a gang member because of his appearance. Mitchell denied the assertion.

The prosecution is expected to rest its case on Wednesday.

Griffin was indicted last year on nine criminal counts after a lengthy FBI investigation. He has pleaded not guilty to all the charges.

Libor Jany • 612-673-4064 Twitter:@StribJany