Rajkumar, 49, a small-time financial agent, allegedly died in custody on June 21 after being subjected to brutal third degree torture at the Nedumkandam police station.
The Monsoon Session of the Kerala Assembly that ended on Thursday witnessed several days of protests and unruly scenes over the custodial death with the Congress-led Opposition demanding a judicial probe into it. On Thursday, Rajkumar's mother joined the protest demanding a CBI probe.
This is the fifth allegation of custodial death against the Kerala Police since 2016, when the Left Democratic Front (LDF) government came to power.
While the Congress welcomed the government's decision for setting up the probe panel, the BJP said that a CBI probe would have been more appropriate.
According to reports, Rajkumar was rounded up on June 12 by a group of people who he owed money to, and handed over to the Nedumkandam police.
The police however, recorded his arrest on June 16 and later shifted him to the state-run Peerumedu Taluk Hospital, where he died on June 21.
Though the post-mortem mentioned pneumonia as the cause of death, the autopsy report revealed 22 injury marks on Rajkumar's body, most below the thighs, indicating that he was subjected to third degree torture while in custody.
While four police officials from Nedumkandam police station have been suspended for the custodial death, two among them have been arrested and are presently in judicial custody. Eight others have been transferred.
Idukki District Police Superintendent K.B.Venugopal and his junior official are also likely to face disciplinary action.
According to sources in the Crime Branch, which is probing the case, more arrests of police officials cannot be ruled out.
( With inputs from IANS )