A Minneapolis police officer trailing a group of robbery suspects in an unmarked vehicle late Friday night on the city's North Side rounded a curve into a volley of automatic gunfire that left him with a shoulder wound.

Officer Jacob Spies, a seven-year veteran of the department, was rushed to North Memorial Health in Robbinsdale, where he was treated and discharged.

Minneapolis Police Chief Brian O'Hara, who described the shooting as an ambush, said on Saturday that the gunmen might not have realized they were targeting a police officer.

"I cannot say whether the the suspects in the vehicle believed he was the police or believed he was someone else," O'Hara said at an afternoon news conference with Mayor Jacob Frey. "But it's clear from what happened that they were trying to kill whoever was in that car."

The officer was dressed in an understated blue Minneapolis police T-shirt rather than full uniform and may not have been readily identifiable, O'Hara said.

Four suspects, including a teenage boy, were later taken into custody. Investigators also recovered an unregistered "ghost gun," a firearm that lacks serial numbers.

It's not immediately clear whether the gunmen fired from inside their vehicle or while standing on the street.

The attack occurred on an unusually bloody night in Minneapolis that sent nearly all available police squad cars screaming to priority 1 calls, including a mass shooting on the city's South Side that killed one and injured six others, and a fatal domestic stabbing.

Frey and O'Hara cast Friday night's startling violence as an "aberration" after this year's marked reduction in gunshot wound and homicide victims. As of Friday, 137 fewer people have been struck by gunfire compared with this time in 2022, department figures show.

"But obviously yesterday shows we have a whole lot of work to do," said O'Hara, whose hands shook at the podium as he raised his voice to declare: "What happened here is absolutely outrageous."

O'Hara gave this account of the chaotic string of events Friday night:

Just before 8 p.m., officers observed a white Chevrolet Equinox in the area of a robbery that had just occurred at 36th and Queen avenues N. in Minneapolis. Officers from the Fourth Precinct attempted a traffic stop on the SUV. The vehicle had been the subject of an alert for fleeing from Brooklyn Park police Thursday. The vehicle initially pulled over but then fled.

About an hour later, a patrol officer later identified as Spies — who was working on a focused enforcement detail with the Hennepin County Sheriff's Office — saw that Chevy in the area of Dowling and Morgan avenues N. He pursued for about a mile, trailing behind and believing he was undetected while calling for additional officers.

At 9:16 p.m. in the 4300 block of Colfax Avenue N., Spies came around a curve in the road and suddenly found himself in a barrage of automatic gunfire. At least 14 rounds were fired — six struck the squad and one hit Spies in the shoulder, where he was unprotected by his armor.

He drove west on Webber Parkway to Fremont Avenue N., where a backup officer pulled him from the vehicle and raced him to the hospital. (Top police officials declined to name the injured officer, but three sources with knowledge of the investigation identified him as Spies to the Star Tribune.)

Shortly after the shots were fired, backup officers saw the same Chevy Equinox in the area of 42nd and Lyndale avenues N., O'Hara said. Several squad cars began pursuing the vehicle and attempted a traffic stop, but the driver refused to pull over. A high-speed chase ensued to 21st and Upton avenues N., where the suspect vehicle crashed into a parked car.

Two men, one woman and a teenage boy were arrested. All three males were hospitalized with injuries, including one man who was bitten by Hennepin County Sheriff's Office dog, officials said.

"That particular block, the way it's set up — with a hillcrest, on a grade and on a curve — is quite frankly a perfect area for somebody to be ambushed," O'Hara said.

"You wouldn't see it coming," he added.

Frey described the shooting as a harrowing reminder of the dangers law enforcement officials face each day.

"These are human beings that are stepping up to run towards danger when so many of the rest of us would run in the opposite direction," he said.

On Saturday, community activists circulated a Facebook post purporting to show a 16-year-old boy in a hospital bed with a bloodied face and one eye swollen shut. The post accused police of beating the teen so badly during an arrest that he suffered a shattered skull, broken facial bones and internal injuries.

Questioned about that account, O'Hara said he was aware of the allegation but personally watched dashcam video of the crash and subsequent arrests and saw no evidence of excessive force by his officers.

O'Hara said he planned to bring in community leaders to review the videos and that any use of force would remain under investigation.

Lisa Clemons, a retired police sergeant and founder of the street outreach group A Mother's Love Initiative, told the Star Tribune that she and two Black faith leaders were invited to view that footage Saturday. Videos showed the boy exiting the back of the vehicle with a bloody face after the crash — injuries clearly sustained during impact, she said. He then laid on ground until officers cuffed his hands and sat him on the curb.

"They showed restraint," Clemons said.

As of Saturday, the boy remained hospitalized in stable condition with what O'Hara described as "non-life-threatening injuries."

Spies was released from North Memorial about 1:30 a.m. Saturday.More than 120 Minneapolis and suburban officers waited outside with hospital staff to salute him. The show of support moved his wife, Holly, to tears.

The crowd applauded as Spies slowly walked to his SUV parked in the ambulance bay. Then Squad 1 — O'Hara's car — led them away.