The judge who will alone oversee the trial of the accused Claremont serial killer will provisionally accept prosecution evidence that key moments in the messy breakdown of his first marriage corresponded with the murders.
Former Telstra worker Bradley Robert Edwards is charged with murdering secretary Sarah Spiers, 18, child care worker Jane Rimmer, 23, and lawyer Ciara Glennon, 27, after they spent a night out in the wealthy suburb's pubs in 1996 and 1997.
On Friday, Supreme Court Justice Stephen Hall said he would allow the "emotional upset" evidence to be adduced at trial with a view to making a final ruling on it no later than the close of the prosecution case.
The marriage unravelled after Edwards became increasingly distant, staying up late on his computer, while she developed feelings for a male housemate.
Edwards walked in on them kissing, which caused an argument, but he rejected the man's offer to leave the house.
After she moved in with the man, Edwards called him and said "you've been having an affair with my missus" then became threatening, saying he knew where he lived, but the man never heard from him again.
Months later, Edwards did not outwardly react when she told him she was pregnant to the other man, but the prosecution argues the impact must have been significant and Ms Rimmer was murdered days later.
Justice Hall also said evidence from psychological reports taken after Edwards was convicted for attacking a social worker from behind and trying to drag her into toilets at Hollywood Hospital in 1990 could be adduced at trial.
Edwards said he didn't know why he did it, but volunteered work frustration, pressure to get married from the woman who ended up becoming his first wife and her confession to infidelity earlier in their relationship.
Justice Hall ruled the reports were critical evidence.
"Without that evidence it would be very difficult, if not impossible, for the state to maintain that any of the emotional upset evidence has any relevance," he said.
Justice Hall said it was "capable of supporting an inference that the accused may respond to acute emotional upset in his life by attacking a female stranger with a sexual intent".
But it was the only proven instance and there was no evidence of acute emotional trauma surrounding Edwards' attack on an 18-year-old woman in her bed in Huntingdale in 1988, and the abduction and double rape of a 17-year-old girl at Karrakatta cemetery in 1995.
The 50-year-old made those shock admissions last month.
Justice Hall was unconvinced by the prosecution's argument Edwards was upset by the sale of the matrimonial home before Ms Glennon's murder, as the transaction occurred 12 days prior.
He also said the first wife's refusal to attend Australia Day fireworks with Edwards hours before Ms Spiers vanished possibly "assumed greater importance" in the context of their recent separation.
"There is no general rule of human behaviour that the suffering of emotional upset, distress or trauma, to any particular degree, will result in homicidal violence," Justice Hall said.
Australian Associated Press
