Authorities hunting killer of policeman in Northern Ireland seize gun , ammunition . 3 more arrests over killings of Two soldiers and officer . Massereene bombs hurled at police after earlier arrests of two men . six republican groups have reportedly claimed responsibility for the killings .
Authorities hunting killer of policeman in N. Ireland seize gun , ammunition . 3 more arrests over killings of two soldiers and officer . Petrol bombs hurled at police after earlier arrests of six men . Two republican groups have reportedly claimed responsibility for the killings .