Do you know without doubt he's in NY? Could he have told you that to put you off the scent?
Can you call his office switchboard in NY and ask for him to check? Google it.
Pretend you're a business contact rather than personal, make up a name and company name. If they put you through, hang up. If they say they don't have an employee by that name, then you have your answer, although he may not have started there yet if he's gone over with a child and took time out to organise childcare. Try again in another week.
Once you've checked that he is NY, you need to get on a plane, go to his office and loudly tell the whole office he's abducted your child. Refuse to leave until he's come out to speak to you, let them call the police and tell them they need to check the child's welfare as you are extremely worried about his state of mind and as her parent, you are entitled to know the address she's living at.
Take someone with you as support and ensure you have her birth certificate, proof of residency, school reports, GP appointment letters and anything else that proves habitual residency, together with emails, texts showing your access arrangements and him saying he was taking her without permission.
He may not give her back but at least everyone will know what he's done, you've checked the child's welfare and the police will see that she wants to go home so may help.