The attack took place in Vallanadu of Tuticorin district, about 650 km from Chennai.
All the three student attackers have been nabbed, police added.
L.R.D. Suresh, 53, principal of the Infant Jesus College of Engineering and Technology, was fatally attacked for suspending a fourth-year student, P. Pichaikannan, a few days back.
Action against Pichaikannan was initiated following an internal college inquiry that found him guilty of a violent act in a private bus.
Upset at his suspension, Pichaikannan and his two friends, fourth-year student G. Dannis and third-year student M. Prabhakaran, of the same college attacked Suresh with sharp weapons in the morning and ran away.
Other faculty members and students rushed the principal to a hospital, where doctors pronounced him dead and sent the body for the post-mortem examination.
Demanding action against the attacker students, MDMK leader Vaiko blamed the recent movies with violent scenes and the availability of liquor for the unfortunate incident.
"Big and small screens - cinema and television - are to blame for this situation. Many schools have discontinued moral instruction classes and this is also one of the reasons for students behaving in a violent manner," M. Ponnavaiko, vice chancellor of SRM University, told IANS.
Last year, a Class 9 student of St. Mary's Anglo-Indian School here stabbed his Hindi teacher, Uma Maheswari, to death for complaining to his parents about his poor academic performance.
--IANS (Posted on 10-10-2013)