Yesterday the tipping point for the four judges seems to be the case of Judge Brijgopal Loya. Two petitions demanding a fair probe into his mysterious death were listed before a bench that is headed by a judge who is 10th in terms of seniority. They believed a matter as serious as this should have been heard by someone more senior.

Judge Loya, who died under mysterious circumstances in November 2014, was hearing the Sohrabuddin Sheikh fake encounter case dating back to 2004, in which various police officers and Bharatiya Janata Party president Amit Shah were named. Shah was discharged in December 2014.

Latching onto media reports that the prime minister's principal secretary turned up at the chief justice of India's residence, the Congress on Saturday said Prime Minister Narendra Modi must answer as to why a "special messenger" was sent to the CJI.

TV visuals showed prime minister's Principal Secretary Nripendra Misra driving to the residence of CJI Dipak Misra.

However, the gates were not opened and after waiting for a while, he left.

The development came a day after four senior-most judges of the Supreme Court virtually revolted against the CJI, raising questions over "selective" case allocation.

After the TV visuals were aired, the Congress was quick to criticise the government.

"As PM's Principal Secretary, Nripendra Misra visits CJI's residence at 5, Krishna Menon Marg ; PM must answer the reason for sending this special messenger to Chief Justice of India," Congress's chief spokesperson Randeep Singh Surjewala tweeted.

Terming the concerns raised by the four judges as "unprecedented and sensitive", the Congress had on Saturday demanded a probe into the issues flagged.

On the other hand, the BJP had charged the Congress with "politicising the internal matters" of the judiciary.