DETROIT (WWJ) – The caption says simply: “This happened in Downtown Detroit last night.”

And then starts a video that shows about 25-40 men punching, kicking and brutally beating people on the streets of Greektown, one of Detroit’s most popular hotspots. In the video, one man is lying with his head over the curb appearing unconscious and very badly injured. He gets punched and kicked as the cell-phone filming crowd of young men shouts and laughs.

(Click: Watch on Facebook)

Quickly becoming known as the Greektown brawl — the Saturday night fight was caught on video that was posted to Facebook.

By the time the police in Detroit were alerted to what was happening it was already over, they said. Police Chief James Craig said the department is vigorously working to uncover who was involved in the “troubling” incident.

Eight perpetrators have been identified, he said. They had all parked at Greektown casino, one in a rental car.

“Our message is ‘We know who you are, we are going to get you and arrest you so do yourself a favor and turn yourself in,” Craig said during a Monday morning presser. “In a matter of hours, we will have your identification.”

The family of the man seen with his head on the curb told myfoxdetroit.com he was at the casino celebrating his birthday when he was attacked. He is recovering from a skull fracture and other injuries, they said.

It’s unknown what caused the melee or if the young men knew each other or if one group was randomly attacking strangers. “They left that young man for dead, this is a serious situation and we’re not taking it lightly,” Craig said, adding the incident might be gang-related.

This follows a stabbing incident in Detroit’s Rouge Park, where people posted video on Facebook but no one called police. Both incidents disturbed Craig especially for the fact people watched — and celebrated — without calling police.

“At a minimum, you call the police … If you can’t do that because you’re too busy doing Facebook live, maybe going forward we should look into charging people who spectate,” Craig said.

He later added: “As a society, what have we become?”

If anyone recognizes anyone in the video or has any information pertaining to this crime please call the Detroit Police Department at 313-596-1616, 313-596-1855, 313-596-2260 or CRIMESTOPPERS at 1-800-SPEAK-UP. Citizens can remain anonymous, as always by leaving a tip on our app, DPD Connect.