An internal investigation by Faridpur district police has recommended departmental proceedings against the then officer-in-charge (OC) of the Detective Branch (DB) and 10 other police personnel over the custodial death of banned Bangladesh Chhatra League (BCL) activist Mirza Ishtiaq Ahmed Pranto.

The investigation report has already been sent to Police Headquarters for further action, Faridpur Superintendent of Police Shahriar Muhammad Miajee said on Tuesday.

"The internal investigation recommended initiating departmental proceedings against the 11 DB members, including the OC, and taking disciplinary action against them," Shahriar told reporters.

Pranto, 27, a resident of West Gondhardia in Madhukhali upazila, was picked up by DB police from in front of his house along the Dhaka-Khulna highway on June 20.

According to police, he fell ill while in DB custody and died at Faridpur Medical College Hospital the following day.

A student of Faridpur Law College, Pranto also worked as a seasonal labourer at Faridpur Sugar Mills.

On June 21, Sub-Inspector Ahaduzzaman, who participated in the operation, filed a narcotics case with Madhukhali Police Station, claiming that 100 grams of cannabis had been recovered from Pranto.

The case statement said the raid took place around 2:00am on June 21 and alleged that Pranto admitted possessing the drugs before handing them over from the pocket of his trousers in the presence of two witnesses.

However, a video that later emerged appeared to show the operation taking place in daylight, with Pranto wearing a lungi rather than trousers.

The two witnesses named in the case also told investigators they were not present during the alleged drug recovery and had signed documents later after being misled and intimidated.

Pranto's mother, Khadija Akter, alleged that DB personnel initially demanded Tk65,000 for her son's release on the night he was detained and later asked her to bring Tk100,000 the following morning.

She said she arrived with the money only to receive her son's body.

Following widespread public criticism, the district police formed a three-member internal investigation committee headed by Additional Superintendent of Police (Administration and Finance) Fatema Islam.

The committee also included Additional Superintendent of Police (Crime and Operations) Md Shamsul Azam and district Special Branch OC Mosharraf Hossain.

Shahriar said the probe found that all officers involved in the operation bore some degree of responsibility and recommended a departmental inquiry to determine each individual's role before further action is taken.

He, however, declined to comment on specific inconsistencies in the case, including the alleged drug recovery, discrepancies over the timing of the operation, the presence of witnesses and allegations that money was demanded from the victim's family.

Following the incident, the then DB OC and the 10 other police personnel involved in the operation were attached to the Faridpur Police Lines.