Judge Ian Gray on Friday ruled he could not reach the required standard of proof of who killed Mr Hodson and wife Christine, who were shot dead in their Kew home between May 15 and 16, 2004 after Mr Hodson had agreed to give evidence against allegedly corrupt police.

Former drug squad detective and Wangaratta resident Paul Dale and hitman Rodney Collins were charged in 2009 with murdering Mr Hodson, after underworld boss Carl Williams implicated both men. Collins was also charged with murdering Ms Hodson.

But the case against them collapsed when Williams was murdered in prison in 2010. Mr Dale and Collins – in jail over an unrelated double murder – deny any involvement in the murders. Police cleared them of any involvement in Williams' murder.

Judge Gray told the Coroners Court that Williams was capable of organising the murders and Collins was capable of carrying them out.

But because Judge Gray did not accept Williams "as a witness of truth or any of his accounts as inherently reliable", he was unable to conclusively support the police theory that Mr Dale asked Williams to arrange the murder, and that the crime boss recruited Collins.

Judge Gray also found that while police could have helped bolster security at the Hodsons' home, Mr Hodson did not heed advice to stay out of his favourite television room, where the couple was found dead.

One of the Hodsons' daughters, Nikki Komiazyk​, shook as she read a statement outside court, in which she said her parents had partly been blamed for their own deaths, and repeated a call for a royal commission into police corruption.

"We can never move forward and ... there's no justice for us, there's no justice for my parents," she said.

Fairfax Media reported on Friday that police might charge Mr Dale with fresh corruption offences over his relationship with Williams. 

A lawyer for Mr Dale declined to comment on the findings.