Police kept the corpse of Aminur Rahman Tipu, 55, former president of Ziarakhi union unit BNP under Sadar upazila, in the hospital on Wednesday morning.
Tipu, a resident of Kamalapur village under the upazila, was assistant teacher of Barokhadat High School.
Tipu's wife Nazmun Noor said some one called her husband out of home over phone on Tuesday evening and since then he remained missing along with his motorcycle.
Later, they were noticed that some unknown people took him to the outdoor of the hospital where the physicians announced him dead.
Nazmun claimed that their rivals tactfully killed her husband as sequel to the previous enmity.
Kushtia model police station Sub-inspector Abdul Aziz said: “The body's post-mortem has been completed and the cause would be known after its report. An unnatural death case has been registered in the incident.”