A notification issued by the Home Ministry on Wednesday (April 8) confirmed the matter.
As per the notification, their appointment will come into effect on April 15.
The tenure of present IGP Mohammad Javed Patwary will expire on April 13.
Benazir Ahmed joined Bangladesh Police as an Assistant Police Superintendent (ASP) in 1988.
He has served in various important positions in the country’s law enforcement agencies, including as chief of Dhaka Metropolitan Police.
He has been DG of RAB since January 2015.