TV news channels in the state have now picked up the pictures, and a discussion has begun about what jail inmates should be allowed to do.
Kodi Sunni, Kirmani Manoj and Mohammed Shafi, among the 36 accused in the murder case, posed within the jail premises, wearing shorts and sunglasses, and posted their photographs on Facebook.
"The director general of police is probing the matter and action will be taken against those found to be wanting in their duty. This (access to social media for prisoners) is not acceptable at all. I am visiting the jail tomorrow to find out for myself what has happened," state Home Minister Thiruvanchoor Radhakrishnan told reporters.
Chandrasekheran, who was ousted in 2008 by the Communist Party of India-Marxist after he became the proverbial thorn in the side of the party in Kozhikode district, founded another party, the Revolutionary Marxist Party.
As the 51-year-old was returning home near Onchiyam in Kozhikode district May 4, 2012, he was hacked 51 times by a group of armed gangsters.
Thirty-six people are in jail as undertrials in this case.
Kozhikode Jail officials said they searched the premises after the news reports featuring the photographs appeared, but could not find anything.
Among the posts on the social networking site left by the three are those claiming that Kerala would soon get a new and excellent chief minister in CPI-M leader Pinarayi Vijayan.
TV channels have uncovered mobile call details showing that Kodi Suni spoke on a cellphone even at 11 a.m. Monday. TV news reports show that more than 900 calls were made by Kodi Suni from two mobile phones in the past two months.
Among those accused in this murder case are state, district and local leaders of the CPI-M, including the husband of a party legislator.
Last month, TV visuals showed CPI-M legislator K.K. Lathika having food with her husband P. Mohanan, one of the accused in the case, in a restaurant, as the man was being taken to hospital for a check-up.
"I am really worried. The case could get blown away because of what we are seeing now," K.K. Rema, widow of the murdered Chandrasekheran, told reporters.
CPI-M legislator and central committee member E.P. Jayarajan, however, said that it was time jail rules were amended.