At least two violent criminals who lived near Corryn Rayney should have been investigated as thoroughly as Lloyd Rayney to eliminate them from her murder inquiry, forensics expert Robin Napper says.
Mr Napper told documentary The Lloyd Rayney Story that Ivin Eades and Allon Mitchell Lacco were living together in the same suburb as the Rayney family at the time of the murder.
Mr Napper, a former British detective, worked on Mr Rayney's defence after reviewing a 600-page forensics report and concluded there was no evidence of a crime at the family home.
He said Mr Eades had convictions for assault and indecent assault but was not interviewed for four months.
Mr Lacco, whose convictions included sex attacks on a girl aged 11 and a woman, 29, in her home, previously lived near the Bentley community centre where Mrs Rayney often went to dance classes. Mr Lacco also admitted dealing drugs in the carpark.
Mr Napper said that after Mrs Rayney's body was found, Mr Lacco was arrested on minor traffic charges and had injuries to his eye and hands that he blamed on a dog attack. There was also sand in his car's boot.
He said the Rayney investigation team was told of Mr Lacco's arrest but his car and clothes were not examined.
Mr Rayney's lawyers identified Mr Eades and Mr Lacco in cross-examination of police witnesses at his trial. At the time, Justice Brian Martin said the defence seemed to suggest the men were "alternative" suspects.
The trial was told DNA matching Mr Eades, described as "well-known to police", was on a cigarette butt outside the Rayneys' home.
Later Mr Rayney's lawyer withdrew references to evidence which might have suggested either Mr Eades or Mr Lacco were implicated in the murder.
He said the defence had no onus of proof and did not have to put forward an "alternate killer".
In his decision, Justice Martin criticised some police involved in the case but said there was "no evidence that lines of inquiry were not properly investigated".