VIDEO: Police search for gunmen in Florida concert shooting that killed 2, wounded 21

HIALEAH, Fla. – The investigation into who is responsible for a mass shooting in Northwest Miami-Dade continues with information trickling in about what led to 21 people being injured and two killed at the scene outside of a banquet hall early Sunday morning.

News 6 partner WPLG has learned that the gunmen reportedly waited about 40 minutes for people to start coming out of the venue and that’s when they started shooting. Investigators also believe some of the people in the crowd returned fire.

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“This is a despicable act of gun violence,” said Miami-Dade Police Director Freddy Ramirez. “A cowardly act.”

The Miami-Dade Police Department released video Monday morning of the three armed suspects exiting a vehicle and running with weapons in their hands.

According to police, the shooting took place after a party for a local rapper known as ABMG Spitta, whose real name is Courtney Paul Wilson.

“Well, we know now from the evidence that’s coming out is that there was return fire from the patrons when when these subjects began firing. There was returned fire. There’s multiple casings throughout the scene that establishes that, however, we don’t know at this time who were the shooters that were returning fire and we don’t know yet,” Ramirez said.

Detectives continued to scour the scene in the Country Club Shopping Center at El Mula Banquet Hall, located at 7630 Northwest 186th St., for evidence Sunday, searching for anything that could lead them to the shooters. Police said there were three gunman and that they fired indiscriminately into the crowd outside of the banquet hall before getting into a white Nissan Pathfinder and driving off.

A retired Miami-Dade police commander in the district where it happened said the Country Club Shopping Center has been trouble in the past.

“The very first that we do on a major scene like this is try and identify as many witnesses as possible, as many videos as possible and identifying where all the victims are,” said Ignacio Alvarez, a retired major with the Miami-Dade Police Department.

Now an attorney, Alvarez was commander of the Northwest District from 2012 to 2016.

" . . .Fights, disturbances. What happened last night is unprecedented. It’s never happened before, but it’s an area that was an area of concern for us because you had constant calls,” he said.

[RELATED: Police: 2 dead, at least 20 injured in South Florida concert shooting]

Alvarez said that detectives are looking through surveillance video and interviewing witnesses and trying to pin down those suspects in the Pathfinder, who they are and why they opened fire.

“All the video that’s being downloaded, they’re going to be going through it trying to recognize faces, running it through facial recognition . . . even show them to the victims themselves to try and identify who they are as fast as possible,” Alvarez said.

But he says the best way for them to be caught is for those with information to come forward.

“People saw what happened, people saw the car, people saw the fleeing, people saw the faces, people need to get involved so shootings like this can stop,” Alvarez said. “This is not just a police investigation, the police are going to need the community involved.”

Miami-Dade State Attorney Katherine Fernandez Rundle tweeted that her gang prosecutors and investigators are working with the Miami-Dade Police Department to identify the shooters.

There is also a reward being offered by Miami-Dade Crime Stoppers that is now up to $30,000 for any tip that leads to an arrest. Call them at (305) 471-8477.

Also, to encourage people to come forward, businessman and television personality Marcus Lemonis sent out a tweet announcing that he was offering a $100,000 reward for tips that could lead to the arrest and conviction of the suspects.