The NYPD will 'flood the system with uniforms' after multiple people were shot in a Brooklyn subway station, former NYPD captain says

• The NYPD will put "several hundred" more officers in the subway system after Tuesday shooting, a retired NYPD captain said.
• On Tuesday morning, a gunman opened fire at a Brooklyn subway station, leaving more than a dozen injured.

In the days to come, the New York Police Department will deploy "several hundred" officers to various subway stations around New York City in response to a shooting that left multiple people injured, a policing expert told Insider.

A man wearing a gas mask and a construction vest shot at least six people in a Brooklyn subway station Tuesday morning. More than a dozen were injured.

Officers with the New York Police Department have not yet caught the gunman, and they're expected to conduct a "lengthy investigation" to determine his identity and motive, said James Dooley, a retired NYPD captain who's now a professor at John Jay College of Criminal Justice.

The NYPD will also rev up security, Dooley told Insider.

"They're going to flood the transit system with uniforms," he said.

"They're going to put several hundred more officers on the high-profile train stations," he said, specifically pointing to some of New York City's most traveled stations like Penn Station and Atlantic Avenue-Barclays Center.

Tuesday's shooting, however, occurred at the 36th Street and 4th Avenue subway station in Brooklyn, which receives comparatively low foot traffic.

Preventing gun violence in small subway stations is "very difficult," Dooley said.

"We don't stop people getting onto the system," he continued. "We don't search people getting onto the system generally. So how do you stop someone from getting on with a device? For the most part, truthfully, we don't — not in a free society."

There are cameras at every subway station, but they're passively monitored, Dooley said. So it's unlikely that anyone behind the camera would catch sight of a potential gunman before they fire.

The gunman behind Tuesday's shooting, though, was wearing a construction vest, and "most people would not even question that," Dooley said.

Commuters who ride the New York City subway system are used to seeing people in construction vests. "They would say, 'Oh, he's obviously a contractor working for the MTA," Dooley said.

The incident will ramp up fears about riding the subway

For months, New Yorkers have been on edge about taking trips using the New York City subway system.

In mid-January, a homeless man shoved 40-year-old Michelle Go in front of an incoming train at the Times Square station. Go was found dead on the tracks; she never saw her attacker. Eight days later, a 62-year-old man was pushed onto the tracks at a Lower Manhattan station. Police said he had to receive treatment for a leg laceration.

Tuesday's shooting will exacerbate that fear, Dooley told Insider, and likely cause daily ridership to plummet.

"People are now going to be afraid," he said. "Especially during rush hour, because this individual did this at about 8:30 a.m."

"It was designed to strike fear in the morning rush hour," he said.

After the police find and debrief the gunman, they're going to scour his house and analyze his social media and any content around the shooting to check for potential red flags and clues that give insight into his motives, Dooley said.

"This is gonna be a lengthy, lengthy investigation," he added. "This is not gonna be wrapped up in a week. This will take quite a while."

While they conduct their investigation, officers from the MTA, which runs the New York City subway system, might be deployed to stations that have less foot traffic, like the site of Tuesday's shooting, according to Dooley.

And if the police determine that the shooting was an act of terrorism, the FBI will get involved and bring in federal resources.