A homicide investigation is underway after a chaotic night at the Long Branch boardwalk, where crowds fled following reports of gunfire, the Monmouth County Prosecutor’s Office says.

Social media posts and surveillance video showed people fleeing and first responders aiding someone on the beach.

Members of the Monmouth County Prosecutor’s Office Major Crimes Bureau and the Long Branch Police Department are involved in the investigation.

Officials say that just before 9 p.m. Thursday, a man was fatally shot in the area between the shoreline and boardwalk of Pier Village. The victim's identity was not immediately released.

Dan McCreesh’s night went quickly from celebrating his new business opening to running for cover.

“When we heard the shots fired, it was certainly scary for a few minutes,” said McCreesh. “I was able to see everything play out, and I mean there was a swarm of 100 cops. They all went to one individual on the beach that was certainly hit."

Many witnesses say they watched a fight on the beach turn deadly.

Huge crowds were on hand to enjoy a warm summer night with live music on the boardwalk.

“We’re having a good time, and it goes from...wanting to celebrate a good time to honestly, putting life in perspective. I’ve never been more impressed, I’ll say, during a time of crisis to where it was all hands on deck and that actually made me feel safe,” said McCreesh.

But McCreesh says those feelings quickly turned somber when he realized the scope of what he just watched play out feet away.

“It was crushing to kind of be real time in that moment because there’s nothing you can say, nothing you can do you have to have empathy," he said.

McCreesh says it’s not the first time this summer he’s seen things get out of hand – but not to this extent.

“It’s probably the third instance this summer – not shooting – but where there’s been fights, big fights," he said.

Back on the beach, crews finished clearing away the trash and getting the sand ready for a busy weekend in the areas surrounded by police tape.

“Something kind of has to be done. I don’t know what that is, but that’s why there are paid people in the positions to do that,” said McCreesh.

Long Branch Mayor John Pallone issued the following statement about the investigation:

"I sincerely regret the loss of life that occurred last night on Chelsea Beach. I want to extend my sincere gratitude to the Long Branch Police Department and the Monmouth County Prosecutor’s Office for their swift and effective response. I would also like to inform the public that the city has reopened the roadway, boardwalk, and beach. These areas are once again accessible and fully staffed with our regular team of beach security and lifeguards."

Officials say that this appears to have been an isolated incident.

The Monmouth County Prosecutor's Office is requesting that anyone who may have videos or pictures of the beach and boardwalk around the time of the incident to share those images. Videos and photos can be uploaded HERE.