The son of slain police informer Terence Hodson was considered a suspect over the execution-style murder of his parents, a Victorian inquest has been told.
Terence and Christine Hodson were found shot dead at their Kew home in May 2004, before Mr Hodson was to give evidence against drug squad detectives Paul Dale and David Miechel in a criminal trial over a burglary at an Oakleigh drug stash house.
Former homicide squad detective Cameron Davey told an inquest into the couple's deaths that a number of people, including the Hodsons' son Andrew, were treated as suspects.
"Andrew Hodson was also the subject of a thorough investigation," Mr Davey told the Victorian Coroners Court on Monday.
"We did and still suspect that the killer or killers had knowledge of the layout of the house and security systems.
"But I don't believe he was personally responsible for the murders."
Mr Davey said police spoke to more than 100 people in relation to the deaths, particularly the people who had been named by Mr Hodson in his informer reports.
Mr Davey also said the woman who was "babysitting" the Oakleigh stash house told police that the man running the operation knew that Terence Hodson was going to be murdered.
The woman said she was instructed to leave her house on the night of the murder and to make sure she was seen, Mr Davey said.
Mr Dale and convicted hit man Rodney Collins were charged with the Hodsons' murders in 2009, but the charges were dropped. Both deny any involvement.
Mr Davey said Collins had once offered to give information about the murder, but only on the condition that he be granted immunity from prosecution, a deal that police rejected.
The inquest, before State Coroner Judge Ian Gray, continues.