The gunfight took place at an embankment of the Gomti River near Cumilla city's Chanpur Ratnabati area in the early hours of Thursday, according to Kotwali Model Police Station chief Anwarul Azim.
Shah Alam, 28, was a native of Bou Bazar in Shuja Nagar.
On Nov 22, a group of masked assailants attacked a cement shop belonging to Sohel in the Pathuriapara area of Cumilla.
They fatally shot Sohel and Haripada Saha, the president of a Sramik League ward unit. Four others were also injured in the attack.
Sohel was elected as the councillor of Ward 17 in 2012 and again in 2017. He was also serving as a member of a mayoral panel for the second time.
Sohel’s brother, Syed Md Rumon, filed the murder case a day after the incident. He accused 21 people and named 11 in the case.
Haripada Saha ‘identified’ Shah Alam as one of the attackers when he was taken to the hospital where he died, said Md Rumon.
Shah Alam was named in several other drug and smuggling cases.
Earlier on Nov 29, Sabbir Hossain, 28 and Sajan, 32, two other suspects in the case, died in a ‘shootout’ with the police in the Sangraish area of Cumilla city.