The police have arrested Khairul Islam Kalu, a key suspect charged in connection with the murder of Mahmuda Khanam Mitu, the wife of former police superintendent Babul Akhter.
Police Bureau of Investigation (PBI) Assistant Police Superintendent Naima Sultana said they arrested Kalu in the Salimpur area of Sitakunda, Chittagong, in the early hours of Saturday.
The PBI later turned him over to local police, she added.
On June 5, 2016, Mitu was stabbed and shot dead when she was walking her son to his school bus stop at the port city's GEC intersection.
Following the murder, Babul Akhter, who was serving as a police superintendent at the time, filed a case in 2016.
The PBI concluded that it had information pointing to Babul's involvement in the murder when it delivered its final report on the investigation in May 2021. Mosharraf Hossain, Mitu's father, later filed a murder case against Babul.
On April 9, Mitu's father Musharraf testified in the opening of the trial for seven accused, including Babul.
Wasim, Anwar, Ehteshamul Haque Bhola, Shahjahan Mia, Musa and Khairul are the other suspects who were indicted.