The City University of New York is investigating whether a recent $500,000 donation intended to bolster the humanities and arts at its flagship school may have been improperly diverted.

The inquiry was prompted by senior faculty members at the school, the City College of New York, who learned that an account that should have contained roughly $600,000, thanks to the donation, had just $76. Faculty members asked City College officials for an explanation, but were met with “silence, delay and deflection” before appealing directly to the university’s chancellor, James B. Milliken. Mr. Milliken then asked Frederick P. Schaffer, the university’s general counsel and senior vice chancellor for legal affairs, to look into the “the expenditure of monies donated,” according to documents obtained by The New York Times.

The account in question — the Martin and Toni Sosnoff Fund for the Arts — is part of the holdings of the City College 21st Century Foundation, the school’s principal fund-raising arm. The finances of that foundation, as well as those of City College’s president and her family, are already being investigated by federal prosecutors in Brooklyn.

In May, The Times reported that the foundation had paid for some personal expenses of the president, Lisa S. Coico, such as fruit baskets, housekeeping services and rugs when she took office in 2010. The foundation was then reimbursed for more than $150,000 from the Research Foundation of the City University of New York, which manages research funds for CUNY, the largest urban public university system in the country. But that arrangement has raised questions of propriety, because such funds are typically earmarked for research.