Plagiarism doesn't just mean copying. But you know that.
From the Harvard Crimson:
Harvard College’s disciplinary board is investigating nearly half of the 279 students who enrolled in Government 1310: “Introduction to Congress” last spring for allegedly plagiarizing answers or inappropriately collaborating on the class’ final take-home exam.
the Ad Board conducted a review of all final exams submitted for the course and found about 125 of them to be suspicious.
So I believe the problem was just the final exam and not multiple exams, although more information will undoubtedly come out.
But a student's own account says:
“Almost all of [the students at office hours] had been awake the entire night, and none of us could figure out what an entire question (worth 20% of the grade) was asking,”
And another of the students admits discussing test questions with other students and says it was commonplace......
then I kind of suspect that the students were working together on the test questions and not just sharing study guides before the exam.
Call me crazy. Or dense. But that's how my blind eyes see it.