https://ttlc.intuit.com/questions/1900655-what-to-do-if-you-suspect-tax-related-identity-theft
Sounds like you filed in time to prevent a problem for yourself for the 2019 return. If the other parent tried to file and claim your child his e-file would have been rejected. If there is ever a time when he filed first and your own return is rejected because he used the child's SSN, then print, sign and mail your own return claiming your child. The IRS will sort it out---and if he received a refund he should not have received he will have to pay it back with penalties.
Do be aware of this though----do you have any signed agreement with him regarding custody? You did not mention if you are divorced or "never married."
Are you the custodial parent? Do you have an agreement with the other parent to allow the other parent to claim them--due to divorce or that you live apart and share custody? Did one of you sign a Form 8332?
If there is a signed 8332 then the custodial parent retains the right to file as Head of Household, get earned income credit and the childcare credit + education credits if the child is a full-time college student. The non-custodial parent gets the child tax credit for children under the age of 17.
As far as the IRS is concerned, the custodial parent is the one with whom the child spent the most nights during the tax year--at least 183 nights.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
