Ottawa County Prosecutor Ron Frantz said there was "no criminal statute that we were aware of that was being violated."
Frantz said his office reached the decision this week after reviewing the case with investigators from the Allendale school's police department.
Evidence led investigators to a current Grand Valley State student, who officials say was interviewed and confessed. The student is expected to face disciplinary action from the school. In a statement, Grand Valley State says it accepts the prosecutor's decision.
The school announced March 21 that fraudulent emails were being sent.