The inquest was played CCTV footage of Baxter in a Brisbane Bunnings Warehouse just after 6pm on February 17, 2020.
In the footage he buys a jerry can and zip ties, items he would use less than 36 hours later.
The next day he was seen visiting a service station where he bought 4.7L of petrol, lollies and three Kinder Surprise eggs.
The inquest heard he called a men’s support service that afternoon.
Audio played at the inquest revealed Baxter blamed his estranged wife for their problems, telling the support service he was the victim.
“My wife, to be honest, it’s almost like a game to put her in a better position for family court,” he is heard saying.
“I’m not the one who has the problem. I’m just doing what I’m told.
“I never even thought my wife was capable of doing anything like this.”
The next morning, February 19, he was again seen on CCTV filling his car with fuel.
A little more than an hour later, he doused Ms Clarke and their three children in petrol whilst they were inside a car, before setting them on fire.
The timeline of Baxter’s movements was established by investigators after the deaths.
A psychologist who treated Baxter told the inquest he displayed three red flags from as early as mid-December, including being controlling and jealous.
Psychologist Vivian Jarrett said Baxter told her he believed he had a perfect relationship.