Delhi chief minister and Aam Aadmi Party convenor Arvind Kejriwal joined the protests at Jawaharlal Nehru University campus in Delhi on Thursday.
Kejriwal, while attending a solidarity meeting at the JNU campus, lashed out at the BJP saying that its leaders are not loyal to anyone, not even to their fathers.
"Ye BJP wale kisi Hindu ke nahi hain, ye apne baap ke bhi nahi hain," ANI quoted Kejriwal as saying.
Kejriwal said that the JNU vice-chancellor is not acting to trace Najeeb as he is "scared" of going "missing" himself if he did so.
The chief minister said Najeeb, who has been missing for over two weeks now, will come back only when Prime Minister Narendra Modi could be made to realise that he is losing votes over the issue.
Kejriwal, who has had frequent run-ins with the Delhi Police, said it will not dare to pursue any investigation in this regard as RSS' students' wing ABVP was involved in the brawl following which Najeeb went missing.
"Whoever will raise any voice against RSS, ABVP or BJP will be called anti-national, will go missing," the AAP chief said.
Kejriwal also wondered why no one from the ABVP who was part of the campus brawl been questioned by the Police. Kejriwal said he has written to Union Home Minister Rajnath Singh and will take a delegation to President Pranab Mukherjee when he returns from his Nepal visit.
Earlier, the JNU administration appealed to students and teachers to "discourage obstructive politics and protests" on the campus as it was hampering the smooth functioning of the university and "unreasonable" demands are being raised through demonstrations.
The appeal by the authorities came in the wake of protests by various student groups and teachers for the last two weeks over Najeeb's case.
Najeeb (27), a student of School of Biotechnology and a native of Badaun in Uttar Pradesh, went missing on October 15 following an on-campus scuffle allegedly with the members of ABVP the night before.
Congress leaders Mani Shankar Aiyar and Shashi Tharoor also attended the meeting.
(With inputs from agencies)