Convicted killer John Hone Haerewa assaulted two women he had relationships with before he battered Allison McPhee to death.
Before Haerewa's trial, which ended in a verdict of guilty of murder on Thursday, prosecutors had asked for the jury to hear evidence of his "propensity" for violence against women.
However, a judge in the High Court at Wellington ruled that the two earlier incidents – in March 1994 and January 2006 – did not have enough similarity with the attack on Ms McPhee, 42, to be a kind of "trademark" that would help the jury decide if he was the killer.
The evidence could be unfairly prejudicial when balanced against what it could prove, Justice Alan MacKenzie said in a judgment suppressed until after Haerewa's trial.
Haerewa, 53, had denied killing Ms McPhee at her bedsit in Newtown, Wellington, on July 22 last year. Earlier that evening a friend had seen them kissing and cuddling, and heard Haerewa ask Ms McPhee to look after him.
The Crown alleged that later the same night Mr Haerewa, who is said to have significant brain damage from alcohol abuse and glue sniffing, broke a wooden stool over her and hit her head at least 14 times using one of the stool legs.
In the two previous incidents he had also targeted the victims' heads using what was to hand as weapons.
In the first case he broke the plastic handle of a spade on a woman. She was said to have suffered extensive injuries.
The second woman was injured when he slapped her repeatedly and attacked her with a trowel.
Justice MacKenzie had ruled out a defence attempt to call psychiatric evidence suggesting that, if Haerewa was the killer, he would have been too drunk to be able to form a murderous intent.
- The Dominion Post