A former FBI special agent spoke with News 12 to detail what the investigation into the Brooklyn subway shooting that injured more than 20 people Tuesday morning will look like.

Kenneth Gray, a senior lecturer of criminal justice at the University of New Haven, says police, FBI agents and Metropolitan Transportation Authority police are hard at work interviewing witnesses and looking at surveillance video.

Gray says the problem is they are missing a key piece of evidence.

"And the camera there covering that platform was not functioning so they don't have immediate film footage except for the film that was gathered by people who were collecting it up and putting it on social media," said Gray.

Gray says there needs to be better security at some of these stations.

"Trains pose a real problem because of the nature that people get on and off at various platforms. There's no checking of baggage or anything," said Gray.

Gray says that specific subway car has been taken off line so police can go through it in their investigation.

New York City Mayor Eric Adams said the suspect used a distraction before shooting his victims.

"The suspect in today's attack detonated smoke bombs to cause havoc. We will not allow New Yorkers to be terrorized even by a single individual," said Adams.

Brian Foley, with the Department of Emergency Services and Public Protection, says Connecticut always has a state trooper stationed in New York that helps to respond to these types of events.

Foley says there is no specific threat here in Connecticut.