Two more killings followed, bringing the death toll from the feud to seven.
His killing follows the death last fall of another popular opposition figure, who was shot twice in the chest and once in the head.
The killing follows a series of brutal attacks on British tourists.
Israeli generals made clear that more such killings could follow.
Four protesters were killed and 24 wounded; other killings have followed.
Gallagher's killing followed internal disagreements over the future of the republican socialist movement.
The other recent killings followed a depressingly familiar pattern.
Those killings followed two attacks on the police on Tuesday.
The killings followed the guerrilla slaying last summer of an American aid worker.
The court heard the killing followed a row over money from the sale of illegal drugs.