The Crown says whoever struck the two blows that killed a 17-year-old boy in October 2009 may never be known.
Five men are standing trial at the Rotorua High Court for the murder of Kaine Lewis in the Bay of Plenty town of Murapara.
David Rewi, Joshua Leslie Whitu, Jerome Rutene, Neville Duss and Hemi Winitana are charged with murder, and with participation in a criminal group.
Norton Taoho pleaded guilty to murder in July this year.
Crown prosecutor Fletcher Pilditch told the court on Monday that Mr Lewis was struck numerous times, but it was two blows to the head that killed him.
During his opening statement, Mr Pilditch said there were two incidents earlier in the evening that led to the attack.
He said Mr Lewis was separated from a group and attacked with various weapons, one of which was sharp.