The detective branch (DB) of police has arrested two suspects behind the sensational killing of top-listed criminal Tariq Saif Mamun, who was shot dead in front of Dhaka National Medical Institute Hospital in broad daylight on November 10.

Based on information, a DB team conducted a drive and arrested the two individuals, Mohammad Nasirul Islam, joint commissioner of the DB, told The Daily Star.

He, however, did not disclose the identities of the arrestees and said the drive to arrest others involved is still underway.

Regarding the identity, another DB official, involved with the investigation, requesting anonymity, said that the arrestees primarily identified themselves as Ibrahim and Rubel.

"We are verifying information; nothing can be disclosed now," the official added.

Investigators said that the duo went to the Sylhet region to cross the border just after the killing. A team of DB police also moved in the direction following digital footprints, the official said.

Sources said that CCTV footage shows a man wearing a white, red, and blue T-shirt running toward the hospital, while two others chase and fire at him from behind.

One of the gunmen is wearing a cap, a blue full-sleeve shirt, and a mask. The other is dressed in a white-and-blue half-sleeve shirt.

Both can be seen aiming their pistols at Mamun as they move forward, firing repeatedly. Moments later, the two fled toward Victoria Park.

Family members said Mamun had gone to court that morning for a hearing in a 29-year-old murder case and was returning home in Aftabnagar when the attack occurred.

The gunmen opened fire from a short distance, killing him on the spot, before calmly walking away.

The man wearing the cap and mask has been identified as Ibrahim alias Lombu Ibrahim, while the other is Rubel.

Investigators said Ibrahim also led the earlier attack on Mamun in front of the BG Press in Tejgaon on September 17, 2023. The two men are members of a notorious gang based in Jigatola, known to operate with 10 to 12 members. Locals refer to the group as the "Chacha-Bhatija gang."