BNP Standing Committee Member Gayeshwar Chandra Roy and Dhaka Metropolitan Police Detective Branch (DB) chief Md Harun Or Rashid were seen having lunch at the DB office together on Saturday.
The DB chief was photographed serving food to the BNP leader.
Earlier in the day, the police released BNP Standing Committee Member Gayeshwar Chandra Roy from custody following his detention during a clash between law enforcement and party members in Dhaka's Matuail.
In this regard, Md Harun Or Rashid said police had brought him to the DB headquarters on Minto Road to "protect him" and a police car was taking him to his home.
Several BNP leaders said police had left Gayeshwar at the party's Naya Paltan office.
A clash broke out earlier in the day between police officers and BNP members and activists in Matuail earlier in the day, which left Gayeshwar injured.
Soon after, police picked him up in a car and took him to the DB headquarters.
Several BNP leaders and activists have been injured in clashes with police in the capital's Dholaikhal, Matuail, Uttara and Gabtoli areas as the party is observing a sit-in program at the key entry points of the capital.