Wouldn’t you say something like, ‘I wonder if the police have had any word on Agnes?’ Even in passing? Or maybe you’d say, ‘I wish the police would stop bothering us about Agnes going missing.’

Nothing like that was said by either Snow or Mark in the three weeks that police had bugs in the house, which means they either couldn’t care less, which stretches my credulity, or else they were passing notes, which is what people who are hiding something tend to do.

Of course the cops also visited the house, but as Snow said in her letter, she didn’t let them get further than the lounge room. Contrary to popular belief, police can’t charge into a private home and demand to search all the rooms, and it’s not as easy as people think to get a search warrant. You need what’s called a ‘reasonable suspicion’ that a crime has taken place. But what crime had taken place? Agnes Moore was missing but nobody was yet saying that she might be dead.

I don’t like to second-guess cops, but to my mind the next press conference – the one they called two days before Christmas with both Ruby and Steven in attendance – was an exercise in what we journos call ‘shaking the tree’.

To explain: when police aren’t getting anywhere in a particular investigation, it sometimes pays to ‘shake the tree’ or make a bit of noise – that can mean holding a press conference or bumping up the reward for information leading to an arrest – to see if it triggers any kind of reaction.

Shaking the tree can put a bit of pressure on a culprit because it’s a sign that neither the cops nor the family are going away. It can lead suspects to do something stupid. For example, they might head out to check on a body to make sure it’s still covered up.

A press conference can shake a new witness out of the tree too. Somebody who maybe saw something suspicious but hadn’t made the connection in their mind with the case at hand. And that is precisely what happened when Ruby and her brother put themselves before the cameras in the run-up to Christmas 2009.

My contact from Rose Bay tells me that he left the press conference, did some routine paperwork, went home for the day, and by morning there was a message from Crimestoppers saying somebody had called in about the missing Agnes Moore.

That person was Lenore Wallace. To be clear, I wasn’t allowed to talk to Mrs Wallace during Snow’s trial. She was a witness, and as such had been warned off speaking to the media until after the trial was over and the jury had made its decision, but pretty much as soon as the trial was over, I made it my business to try to catch up with her.

I remember the day we met. Mrs Wallace has a house in Tempe, in Sydney’s south. She invited me over and offered me a seat in a floral armchair that had doilies over the armrests, and she brought out a tray with proper leaf tea and jam tarts, and I thought, ‘I’m in the home of an old-fashioned Australian lady here!’