A set of Catholic investors said on Monday private-prison operator GEO Group has rejected a shareholder vote designed to shed light on alleged human rights violations in its operation of ICE detention facilities as part of U.S. President Donald Trump’s immigration crackdown.

The government contractor has become one of the biggest benefactors in Trump’s expansion of the Immigration and Customs Enforcement agency, including operating a fast-growing detention center in Southern California. Complaints of poor treatment, including dismal sleeping conditions and a lack of fresh air at facilities run by GEO, opens new tab and others, opens new tab have sparked protests against the administration as it ramps up detentions and pushes for mass deportations.