A youth was shot dead on Sunday allegedly by an activist of Bangladesh Chhatra League at Sheikerbari Palli of Vatra union under Nandigram upazila of the district
The deceased was Saddam Hossain, 35, a resident of the area.
Morsedul Islam, chairman of Vatra union, said Ripon, 30, the BCL cadre, shot his cousin Saddam to death at his residence in the morning and fled away.
Officer-in-Charge of Nandigram police station said the cause behind the killing could not be known.
They were looking into the matter, he said.
Ripon, younger brother of suspended BCL cadre Benazir, was an accused of BCL activist Sabuj murder case, said police sources.
Sabuj was murdered on August 29, 2016, in Fulbaria area of the town.