A retired assistant commissioner of Kolkata Police, a serving inspector, and a home guard — named in a CBI supplementary chargesheet in the 2021 post-poll murder of BJP worker Avijit Sarkar — were sent to jail on Friday.

They were summoned by the city sessions court at Bichar Bhavan and asked to “surrender”. Their bail pleas were rejected after a lengthy hearing.

This is the second case in less than a year in which Kolkata Police officers have been arrested or jailed in cases probed by the CBI.

Trinamool MLA Paresh Paul and two councillors, also chargesheeted in the same case, had moved Calcutta High Court earlier this week for anticipatory bail. The court directed the CBI not to take coercive action against them till August 1.

The CBI submitted its second supplementary chargesheet on June 30, naming 18 accused. Among them were Subhajit Sen, then officer-in-charge of Narkeldanga police station; Ratna Sarkar, then investigating officer of the case when the probe was under Kolkata Police; and Dipankar Debnath, a home guard attached to Narkeldanga police station.

The court had summoned all 18 accused on Friday. Fifteen appeared. Paul, Ghosh, and Samaddar — who had obtained interim relief from the high court — did not come.

During the hearing, the court asked Sen’s lawyer when his client was promoted. The lawyer replied that Sen was promoted to assistant commissioner 19 days after Sarkar’s murder.

“The court said any type of promotion is a reward. The judge said that although the charges are yet to be proved, the allegations remind us of the phrase: ‘when the protector becomes the predator’,” a lawyer quoted the proceedings.

The CBI lawyer told the court that victim Avijit Sarkar’s brother Biswajit had called the police station for help when Avijit was being beaten, but no help arrived.

When asked about the evidence against the others, the CBI said their names surfaced during witness examination. The court asked the CBI why the witnesses were naming the accused “in instalments”.

The CBI has filed one chargesheet and two supplementary chargesheets in the case, which started four years ago.

Of the 15 who appeared in court and sought bail, 11 were granted bail. Four — including the three cops and one co-accused, Sujata Dey — were remanded in jail custody.

Sen retired as assistant commissioner in November last year. Sarkar is now posted as an inspector; Debnath remains a home guard.

In the RG Kar rape and murder case last year, the CBI arrested the then officer-in-charge of Tala police station, Abhijit Mondal. He was granted bail after the agency failed to file a chargesheet within 30 days.