What Did You Do?

"Thank you for the offer, Mr. Vanitas. I shall hold you to that, perhaps for another matter, but for this one, I assure you that we do not require financial aid. In fact, I called you here for a different reason entirely. You see, the government has been adamant about finding the killer, so they have dispatched a small group of superhumans who will be responsible for the investigation. The superhumans you see outside were only hired part-time and they will only be responsible for patrolling the school at random times of the day to reassure both parents and students, but the superhumans dispatched for the investigation will blend into the student and administration body and try to find the killer in that way."