The newly released documents were obtained through a Freedom of Information Act request by Samantha Parsons of UnKoch My Campus, a group that seeks to expose the influence of the billionaire industrialists Charles and David Koch over colleges and universities.

“The biggest lesson we’ve learned is that Koch really demonstrated the way in which any big donor could have influence over academia if the university is willing to agree to those terms,” Ms. Parsons, a former George Mason student, said.

In a Friday message to the university faculty and staff, Mr. Cabrera said that he had just learned that the university had entered into agreements with donors from 2003 to 2011 that gave them the right to participate in faculty selection and evaluation. “Except for the most recent one, these agreements have expired,” he said. Mr. Sandler said the one that had not expired had been voided.

“All but the earliest of these agreements explicitly stated that the final say in all faculty appointments lies in university procedures,” Mr. Cabrera said.

His message came as UnKoch My Campus publicized agreements regarding Koch-funded professorships in economics that it had received through the Freedom of Information Act. Mr. Cabrera did not specifically name the Koch Foundation as the donor he was referring to, but Mr. Sandler confirmed that it was.