Musa Wada, an engineer, has emerged candidate of the Peoples Democratic Party (PDP) for the November 16 governorship election.
He defeated other aspirants, including Idris Wada, his elder brother who is the immediate past governor of the state.
The PDP candidate secured 748 votes while Abubakar Ibrahim, son of a former governor of the state, secured 710 votes.
The immediate past governor of the state polled 340 votes to place number three in the election while Dino Melaye, senator representing Kogi west, came fourth with 70 votes.
The election was disrupted after gunmen invaded Lokoja Confluence Stadium, venue of the primary, in the wee hours of Wednesday.
Voting by the delegates had ended and sorting of ballots were under way when the gunmen stormed the venue.
Votes in eight out of the 10 ballot boxes had been sorted and counted before the disruption.
Ahmad Fintiri, Adamawa state governor, chairman of the electoral committee, was said to have been whisked away to safety by his security detail.
A delegate was killed while some aspirants, including Melaye, sustained injuries.
Fintiri later called a meeting of all the 13 aspirants at the end of which it was agreed that sorting and counting should continue.
A total of 2,388 delegates were accredited out of a total of 2,511 from 21 local government areas of the state.