"(Some persons) had used the students. Police should probe who sneaked into this movement," he said.
"How did it reach (a situation of) lathicharge. Who instigated it, what is the background? Whether to blame the government or police or students or the extremist forces which had infiltrated," for the caning incidents, he said.
He also demanded to know how police could allow unwanted elements to sneak in amidst the students.
"Why did you allow a python or cobra to sneak into a students' protest?" Radhakrishnan told reporters here.