ALBANY, N.Y. (AP) — New York state tax officials have opened an investigation into the Trump Foundation to determine whether President Donald Trump or his charity violated state law.

The probe began about a month ago and was confirmed Thursday by an official with knowledge of the case. The official was not authorized to speak publicly about active investigations and spoke of condition of anonymity.

If evidence of alleged crimes is found, the matter could be referred to prosecutors, who could seek the release of Trump’s tax returns .

The investigation, first reported by The New York Times, follows Democratic state Attorney General Barbara Underwood’s lawsuit alleging Trump and his adult children used money from the charity to settle business disputes and promote his presidential campaign.

The White House says the lawsuit is politically motivated.