The students of Infant Jesus Engineering College at Vallanadu in Thoothukudi were arrested the same day for hacking the 55-year-old principal to death in the campus.
The trio in their bail plea said they had to appear for the semester exams and their future would be in jeopardy if they were not allowed to do so.
Justice C T Selvam rejected the bail plea yesterday.
The three had hacked the principal to death enraged by his directive issued to them to vacate the hostel following complaints of alleged ragging and certain other acts of indiscipline.