Peter Dawson pointed out that Milat's victims were hitchhikers and that 'Lyn didn't drive'.
But Clive Small, the former assistant police commissioner who led the Milat investigation, said it is unlikely Milat was responsible for Lynette's death.
'I would suggest (the chance) is very much next to zero,' he said.
Chris Dawson was arrested earlier this month and charged with murdering his wife Lynette.
His lawyer confirmed Dawson will be pleading not guilty to the homicide charge.
The former high-school teacher and his schoolgirl lover were the focus on a critically acclaimed podcast, The Teacher's Pet.