The appointment comes as the 25-month tenure of IGP Javed Patwary, an officer known to be trusted by Prime Minister Sheikh Hasina, is expiring.
Both new appointments will be effective from Apr 15, according to the notice issued by the home ministry.
Benazir has been heading the elite police force Rapid Action Battalion for around four and a half years.
Before taking the charge of RAB in January 2015, he had worked as the commissioner of Dhaka Metropolitan Police and is scheduled to retire in 2022.
Benazir joined the law enforcement as an assistant superintendent of police in February 1988. He had worked in the UN peacekeeping missions in Bosnia and Kosovo.
Born in Gopalganj, Benazir received his master’s degree from Dhaka University’s English Department. He also has a PhD in business administration from the university’s Faculty of Business Studies.
CID chief Mamun joined police in December 1989. Born at Sreehail village in Sunamganj’s Shalla, the police officer will retire in 2023.