New York City police are searching for a woman who allegedly attacked a 38-year-old transgender woman on the subway and they say the incident is being investigated as a bias attack.

Video captured the exchange on an uptown D train at 125th Street on Jan. 30, according to police. It began with a verbal argument when the suspect asked the victim if she was male or female. Other passengers tried to subdue the attacker.

The victim, Jennifer Louise Lopez, is a transgender advocate. She told NBC 4 New York her attacker punched her in the face, sending her to St. Luke's Roosevelt Hospital where she underwent emergency surgery on her eye.

"Jennifer is probably afraid for her life," said friend Tanya Asapansa-Johnson of Harlem, also a transgender woman.

Lopez took a photo of her alleged attacker and posted it on a transgender community website.

"It's pretty scary when you're attacked for your gender identity," she said.

Police ask anyone with information to contact Crime Stoppers at 800-577-TIPS.