The Chicago Police Department on Tuesday corrected its official narrative of the May 5 lakefront attack that left a 21-year-old suburban man with a fractured skull after spending a day at Oak Street Beach with his girlfriend.

The Sun-Times reported last week that the girlfriend told local Ald. Brian Hopkins (2nd) that she and her boyfriend were walking back to their car at around 6 p.m. in the vicinity of the 900 block of North Lake Shore Drive when they were surrounded by “20-to-25 mostly male offenders.”

The girlfriend described a “completely unprovoked attack” that occurred without warning when she and her boyfriend were “surrounded by this large group” that “started a confrontation.”

The boyfriend was “struck in the head and fell to the ground,” causing a fractured skull that left him in the intensive care unit at Northwestern Memorial Hospital for more than a week.

The victim, his girlfriend and family have asked to remain anonymous.

That day, after the man was hit in the head, a flash mob of teenagers jumped on cars, harassed and intimidated shoppers on Michigan Avenue.

Police Department spokesman Anthony Guglielmi initially responded to the girlfriend’s account by saying, “This was not a flash mob incident but a fight between two groups.”

On Tuesday, Guglielmi corrected that narrative.

“We have very high-quality video of the victim being attacked. Detectives are actively gathering information from witnesses and residents. And we have very good leads in the investigation…Detectives revealed it was not a flash mob, but a small group of young adults or juveniles,” Guglielmi wrote in an email to the Sun-Times.

Guglielmi also acknowledged that the victim’s parents were ignored for four days when they tried to file a police report.

“The responding officer arrived on the scene quickly and escorted the victim and his companion to the hospital, which was the right thing to do. The officer, however, should have created a police report but failed to do so,” Guglielmi wrote.

“The CPD takes that omission seriously, and has disciplined the officer… The officer received a formal reprimand for the incident.”

It’s a good thing CPD corrected its official narrative.

Hopkins, who was back at the hospital on Tuesday, said he has talked to two friends of the suburban couple, who corroborated the story told by the victim’s girlfriend.

“The four of them were walking together and, at one point, the larger group sort of overtook them. The male victim, who was eventually attacked, was separated from his girlfriend,” Hopkins said.

“He turned around to go back and deal with her and that’s when the confrontation ensued. Clearly, when you’re in a group of four and you’re surrounded by a group of 20-to-25, you’re gonna feel intimidated and threatened. It’s highly unlikely that this was a case of a mutual confrontation. That doesn’t make sense to me.”

The Chicago Police Department has issued a community alert that included surveillance photos and a video of the African-American suspect.

“The witnesses described a surprise, blind-side attack where there was no warning that it was about to turn physical and the individual depicted in the video was the one responsible for launching the attack with his fists,” Hopkins said Tuesday.

The alderman hesitated when was asked whether he believes the incident was racially motivated and should be prosecuted as a hate crime.

He would only say that no racial epithets “were described to me, but additional footage is being sought.”

“It’s the State’s Attorney’s responsibility when prosecuting a situation like this to make a determination if it’s a hate crime. I’m not gonna comment on that,” Hopkins said.

Hopkins said he is “less interested in pointing the finger of blame at whoever dropped the ball internally,” delaying the police report filing, than he is in “making sure the case is properly investigated and prosecuted now that we know about it.”

“There’s been an abundance of video collected…Some of it has seconds of valuable footage surrounded by hours of unhelpful footage. So, it’s a laborious process to go through all of this video. In some cases, it’s like trying to find a needle in a haystack,” Hopkins said.