Updated

The family of a man who was beaten over the weekend near a Detroit casino in a brawl that spawned a viral video is speaking out as police vowed Monday to release new photos of the suspects.

"I was hurt to my soul that you would still keep hitting somebody that is unconscious and you kicked him in his face,” a woman who identified herself as the sister of 23-year-old Brandon Putnam told Fox 2.

The video, posted on Facebook, shows a group of men pummeling Putnam early Sunday morning near Detroit’s Greektown Casino as a crowd shouts and cheers.

“This happened in Downtown Detroit last night,” read the caption on the video, which has been viewed nearly 2 million times.

Putnam's sister told The Detroit News that her brother planned to head to the casino to celebrate his birthday when the violence broke out.

“We never made it to the casino,” the sister said. “My cousin said something, and one of those boys from another group thought he had said something wrong to him, so they jumped on him."

Putnam’s sister, who told Fox 2 that she wishes to remain anonymous, said her brother is being treated at a local hospital for head trauma, including a fractured skull and internal bleeding.

His cousins also were injured in the attack, although not as severely, the sister added.

Detroit Police Chief James Craig said Monday that authorities have still photos of the assailants and are working to identify their vehicles, which were captured on video at the casino’s parking garage.

"We know who you are, so turn yourselves in and we'll work with you,” Craig said. “This is totally an unacceptable situation."

Craig said those photos are expected to be released later Monday, The Detroit News reported.

Police said they arrived on scene “quickly” after two 911 calls were made, but by that time, the fight was already over.

The violent incident is the second videotaped fight in a week in Detroit that showed people egging on the participants instead of helping to break it up, The Detroit News reported.

The earlier incident involved a fight between women that ended in a double stabbing.

Anyone with information on the most recent video is urged to call police or Crime Stoppers of Michigan at 1-800-SPEAK-UP.