Sen. Ruben Gallego, D-Ariz., is facing a federal probe for alleged campaign finance violations. 

The investigation follows a complaint by a whistleblower from Southern California, Axios reported, citing unnamed sources. 

According to Politico, Gallego used a political action committee's PAC to fund trips to Disneyland, Disney World, Miami and Chicago with his family. 

Gallego has denied any wrongdoing. A Gallego spokesperson told Axios that the Justice Department's investigation is a partisan attack from the Trump administration.