Police arrested five activists of Bangladesh Chhatra League (BCL) on Monday night over throwing the principal of Rajshahi Polytechnic Institute into a pond on the campus.
The arrestees are suspended BCL joint secretary and the prime accused in the case Kamal Hossain Sourav, Murad, Shanto, Salman alias Tony and Rayhanul Hasan Hasib.
With them, 17 accused have so far been arrested in the case.
Earlier on November 2, a group of BCL activists threw their principal Farid Uddin into a pond on the campus for his refusal to allow two students to fill up forms for examination for inadequate class attendance.
The incident was captured in a surveillance camera.
The Principal filed a case against 57 with Chandrima Police Station in the metropolitan city.
Bangladesh Technical Education Board formed a three-member probe body over the incident with department director SM Ferdous Alam as the head.