subway
This is a representational image of the subway stop in Manhattan, New York, Dec. 5, 2012 Spencer Platt/Getty Images

The daughter of a New York police sergeant recorded a video of a man masturbating on the subway in Brooklyn on Tuesday.

Kristen Vasquez, 26, from Staten Island, told the New York Post that she was waiting for an R train at 86th Street Station in Bay Ridge when she noticed a man following her. When the train arrived around 8:15 a.m. EDT, the man boarded it with her.

“I noticed him walking around pretty close to me, and I got a little weirded out but brushed it off at first,” she recalled. “When I leaned up against the side of the car inside, I noticed another young woman standing across from me and out of the corner of my eye I saw him making jerky movements.”

Vasquez admitted that she was unsure how the man would react if he saw her filming him with her cellphone, but decided to do just that. As discreetly as possible, she took a video of the man staring ahead as he pleasured himself. His genitals were completely exposed.

In the video, the man was seen gawking at another woman inside the subway as he leaned against the compartment gate. At one point, he lost his balance and stumbled forward. So as to not evoke any strong reaction from the man, Vasquez kept pointing the mobile's camera to the ground at various points during the recording.

After her station arrived and she got off, Vasquez said she noticed both the man and the woman he was staring at were still in the compartment. Not wanting to leave her fellow rider on the train with the masturbator, Vasquez said she grabbed her arm and urged her to get off with her.

Vasquez immediately reported the incident to train conductor, who notified police. She was working with investigators to catch the perpetrator. “It was very traumatic for me,” she said. “I want him caught.”

According to Find Law, “New York criminalizes exposure of a person, one of several offenses ‘against public sensibilities,’ where a person appears in a public place and exposes [or does not clothe] the private or intimate parts of his or her body.” According to the city’s laws, anyone charged with public exposure faces up to 15 days in prison and a fine of $250. On the other hand, public lewdness in the city can be punishable by up to three months in prison and a maximum fine of $500.

Forensic psychologist Stephen Hart, told lifestyle magazine Very Well Fit that flashers or people engaging in public indecencies were "motivated by a specific form of mental disorder known as a 'paraphilia'" which meant that their minds were governed by a “strong, persistent, and preferential pattern of sexual arousal to exhibiting themselves.”

“Flashers want to impress you, the same way everyone dresses — or undresses — to impress. Some people want to impress others as nice, safe, and calm, whereas others want to impress as sexy, exciting, or even shocking. For some people, making a bad impression is better than making no impression at all… In fact, they get more satisfaction doing this than actually having sex with another person [which is part of what makes it a mental disorder],” he added.