The victim J S Sidharth (20), a second-year Bachelor of Veterinary Science student, was found dead on February 18.
The SIT arrested prime accused K Akhil (28) and a PHD student hailing from Pattambi in Palakkad district on Thursday.
The Students Federation of India (SFI) Unit secretary Amal Ihsan and KVASU college union president K Arun surrendered before the SIT late at night.
Opposition student organisations like Kerala Students Union (KSU) and ABVP have been organising protest agitations demanding the arrest all the accused in the case.
(With UNI inputs)