Four people, including a candidate in next month's election, are still being held hostage in Papua New Guinea's Southern Highlands province.
The hostages were taken on Friday, allegedly by the supporters of a current MP in the province.
They had earlier shot dead a policeman.
Our correspondent in Port Moresby, Peter Niesi, reports.
"The people who were involved had tried to get police to release one of their own men who had been arrested for being in possession of firearms and naturally police refused and it was because of that, that people reacted and shot the policeman and took the four others hostage."
Peter Niesi says the name of the MP involved has not been made public.
The killing is the worst example of pre-election so far.
It occurred near where a recently resolved three-year-long tribal fight left more than one hundred people dead.
The ousted Governor of Southern Highlands, Anderson Agiru, is reported to be travelling to the area to negotiate the hostages' release.