If the child has been in LA then LA has jurisdiction and not TX. Therefore any petition should have been filed in LA.
Also, something to note.. if he fails to return the child after a visitation then there is little you can do until the hearing.
When is the hearing ? Where was the divorce petition filed ? Do you have any proof that he only wants the child to get out of support ? How old is the child ?
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Psst.. I am not an attorney, and even if I was, I would not tell you. Which technically could mean I am an attorney, but I would not tell you either way. What I am giving you is not legal advice in anyway. For proper legal advice, retain a person who openly admits they are an attorney.