Most of the nine picked up on Thursday on suspicion of having link with the killing were released yesterday as police did not find their involvement in the incident.

Security measures have been beefed up in Dhanmondi areas following the incident with several patrol teams of police, Rab and Army still roaming around the place of the incident.

Almost every motorbike was checked in the city yesterday as incidents of mugging using motorbikes have become frequent.

About five places, known as gathering places of youths in Dhanmondi, wore a deserted look yesterday due to the security measures.

Meanwhile, police are looking for the young man seen on video footage of the bank. In the footage, the youth was seen moving suspiciously around Rusho while he was withdrawing the money.

AHM Arefin Alam Rusho, a BBA graduate from North South University and son of Lt Col AHM Shafikul Alam and Lt Col Ambory Begum, was shot dead by unidentified muggers in Dhanmondi on Thursday after he came out of Satmasjid branch of NCC bank after withdrawing Tk 4.45 lakh.

Muggers also took away the money.