NEW YORK (CBSNewYork) — State investigators teamed up with the NYPD to catch an alleged sexual predator. The Bronx man is now charged with a new crime in the state of New York — sex trafficking of a child.

CB2’s Cory James talked to neighbors on Saturday about the startling arrest.

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Luis Gonzales did not want to say much, but did speak about 57-year-old Paul Alexander, a convicted sex offender Gonzales said he often saw in a Bronx apartment building.

When asked if he ever saw children going in and out of the apartment, Gonzales said, “Once in a while. Girls used to be looking for him,” adding when asked how often that happened, “Once in a while they would go up there. Always, little girls used to come back and forth.”

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Authorities told James that back in March a girl reported Alexander to the NYPD, claiming he sexually abused her and other girls. She said he also promoted them for prostitution to other men.

Detectives launched an investigation with the help of the state Attorney General Letitia James‘ Organized Crime Task Force, and learned Alexander ran a small charter jet company.

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The AG’s office said Alexander was trafficking children across county lines.

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James reached out to Alexander’s company and team members listed on a website for comment. Three people answered, but all declined an on-camera interview.

Alexander is facing multiple charges. If convicted, he could face 50 years in prison.

Alexander remains in jail and is expected to return to court Tuesday.

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He is also the first person to be charged with the newly enacted crime of child sex trafficking, which increases prosecutors’ ability to hold sex traffickers accountable, James reported.