A U.S. senator wants Donald Trump's modeling agency to be investigated after allegations surfaced last month that three former models had worked illegally in the U.S. while employed by Trump Model Management, Mother Jones reported Sen. Barbara Boxer wrote a letter addressed to León Rodríguez , the director of the U.S. Citizenship and Immigration Services (USCIS) — an agency that’s part of the Department of Homeland Security — and copied to Labor Secretary Tom Perez."I am extremely concerned by the claims levied against Trump Model Management, and ask that you open an investigation into the company's employment practices," she wrote. “I hope you will make clear that immigration and labor violations like these will not be tolerated.” Mother Jones exclusively reported in late August that the former models had worked in the U.S. while on tourist visas. This is strictly prohibited under the current immigration laws.On social media, Sen. Boxer shared the story and criticized Trump's current immigration stance.