LOS ANGELES — Ron Allice, the track and field coach at the University of Southern California, assumed bad news was on the way when Donna Heinel summoned him to her office back in 2011.

He was right.

Heinel, the athletic department administrator who functioned as a gatekeeper over whether recruited athletes could find a spot at the increasingly competitive private university, had found a problem with the track athlete Allice was pushing. He had taken a sign language class to fulfill a foreign language requirement and, though that was the standard in the state university systems, Heinel dug in against him.

Now, Allice wonders if there was another reason Heinel was so resolute. And he is not alone.

Heinel, 57, who as an unyielding, by-the-book administrator rose to a position of unchecked authority during her 16 years in the U.S.C. athletic department, has emerged as a central figure in the academic admissions scandal that has ensnared members of rich — and in some cases famous — families. They are among 50 people charged with carrying out a series of bribes and rigged admissions qualifications, including making up athletic accomplishments, in order to get affluent children into prestigious universities across the country.

Nowhere was the scheme more widespread than at U.S.C., where four others who have coached there — one of them until earlier this month — are under indictment. Heinel stands accused of being at the fulcrum of the scheme, conspiring with Rick Singer, a private admissions consultant, to obtain millions in bribes and then easing more than two dozen students into the school through the so-called side door of athletic admissions, using fraudulent athletic profiles.