At least 20 people took part in the murder of Rifat Sharif in Barguna on June 26, investigators said based on information gleaned from two accused arrested recently.

“The attackers told investigators that they joined the killing mission after dividing themselves in small groups,” a top police official, involved in the probe, told The Daily Star yesterday.

Asked, police officials in the district said one group was tasked with stopping pedestrians from walking near the spot where the attack would be carried out. Another group stood guard near some parked motorbikes so that the killers could flee on them without any hassle after the murder.

Investigators did not give the names of all the 20 for the sake of probe.

Earlier, police said they had identified 13 suspects in the case filed over the killing of 25-year-old Rifat Sharif, who was hacked to death in broad daylight in front of his wife near Barguna Government College.

Footage of the attack, captured possibly on a mobile phone camera, went viral on social media.

The main accused, Sabbir Hossain Nayan alias Nayan Bond, was later killed in a so-called gunfight with police.  Another attacker Rifat Farazi is now on a seven-day remand.

Talking to The Daily Star, an investigator said Waliaullah, one of two arrested accused, confessed that he took part in the attack on receiving instructions on a Facebook messenger group named “007”. Waliaullah, however, claimed that he was unaware about the reason of the attack, the investigator said.

Tanvir admitted that he too received the same instruction on the messenger group.

Asked, the investigator said analysing the history of the group they found that it had some 120 “active members”. The official, however, said some members already left the group after its name surfaced in the media.

“We are now keeping an eye on the group members, including those who left the group,” the official added.

Asked about the mastermind, top police officials in Barguna said they were still interrogating those arrested in connection with Rifat murder.

They said they were hopeful about unearthing the name of the mastermind soon.

Barguna Sadar Police Station Inspector Humayun Kabir, also the investigation officer of the case, said their IT experts were working on the messenger group. “We are investigating the case with utmost priority. We are hopeful about arrest of all the culprits soon,” he told this newspaper yesterday.

Meanwhile, Shahida Akter, mother of prime accused Nayan, demanded a fair investigation into killing of Rifat.

While talking with this newspaper yesterday, she requested the investigators to identify the people who were “responsible for making her son a gangster.

“My son was a very bright student. He has been victimised,” she said.

Yesterday, posters with photos of 12 “killers” of Rifat were pasted on walls in different areas of Barguna town, calling for capital punishment for the killers.

Meanwhile, two accused -- Chandan and Md Hassan -- gave confessional statements last night. With them, four suspects have now confessed to their involvement in the killing, said Barguna SP Maruf Hossain.

[M Jahirul Islam Jewel, our Jhalakathi correspondent, contributed to the report]