The deceased, Sumo Siki, aged 26 of Aipus village, died instantly after being shot with a shotgun from the back, below his shoulders, on Saturday.
As of yesterday, two more men have been reported injured and are currently in critical condition at the Wabag General Hospital.
Wabag police station commander, Inspector John Wasakaman, said the killing was in retaliation between clansmen within the Sikir tribe and nearby Yakal tribes of Kaias village.
He said the mobile squad has been deployed from Laiagam and are on their way down to Wabag.
Inspector Wasakaman further called on the leaders of Enga to talk to their people to stop this killing.
He said they have not started with pre-Christmas operations as yet because of the current conflict in the province.
Situation is still tense.