Ahsan Ullah, 45, was killed around 3am on Saturday near Poddar Bazar in the Upazila, said Lakshmipur Police Station OC Iqbal Hossain.
He lived at Nandipur village under Bashikpur Union.
The ruling party's Bashikpur Union unit President Amir Hossain told bdnews24com that Ahsan Ullah was an active member of his party.
Quoting relatives, Duttaparha police investigation centre's In-Charge Wahiduzzaman told bdnews24.com that the miscreants had attacked and shot the ruling party supporter on his chest while he was on his way home after Sehri.
Police have already sent the body to morgue for autopsy.