As many as 84 students at California’s Diablo Valley College may have paid $600 per grade to have F’s changed to A’s by student employees of the two-year college, according to the Contra Costa Times.

The newspaper says that a 15-month investigation of grade changes at the college is winding down, and that the campus police are preparing to turn over evidence of falsified grades to local prosecutors. The college had authorized more than 100 people across its three campuses to change grades in its computer system, and officials believe a group of student employees took advantage of lax procedures to run the grade-changing business, sometimes altering transcripts by using the computers of regular employees who had stepped away from their desks.

Many of the students who paid to have grades changed have since transferred to four-year institutions, the paper said. It added that the college had known about the problem for more than a year but had refused to release details. —Lawrence Biemiller