Things we know:
1.) One of the two adults gave Narcan to the child. The only reason to give Narcan is to reverse the action of opioids.
2.) Mother had non-lethal levels of morphine and codeine in her blood but no CO from smoke.
3.) Mother was scheduled to perform surgery that morning.
4.) Child found in upstairs bedroom.
5.) Mother found in upstairs bedroom.
6.) Father had no drugs in system, found in garage which was least burned area.
Scenario #1 - Father killed mother during an argument either the night before or very early that morning by striking her on head with something, fracturing her skull. She was abusing opiates and had opiates in her system, but not a lethal dose. And she kept Narcan in the home "just in case".
Father panics. Administers some opioid to child as child sleeps in order for the child not to awaken and find mother dead.
Father decides to cover murder of wife with a house fire. He plans to "save" child but will be "unable to save" mother. Immediately prior to setting fire in family room, father administers Narcan to child in order to reverse opioids he had given to child. He plans to set fire, then go up and rescue child from the fire.
He sets fire and it is immediately out of hand. Too much accelerant. He is engulfed by flames/smoke. In panic he attempts to flee via garage, where he is overcome by smoke and dies.
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The arson investigators may solve this crime by determining what accelerant was used. For that house to have been engulfed and leveled like that, there had to be a heck of an accelerant. Gasoline? Did father spill some on himself? Did a gas can explode while in his hand?
There is likely info from father's autopsy that has not been released. Wonder what injuries/burns his body had? It said he was the least burned.
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I cannot think of a plausible scenario where the mother is drugging the child and starting the fire. And I think whoever drugged the child also started the fire.
The father "worked for the mother". So he was her Practice Manager? Giving access to the money. Wonder if he was stealing from the practice? Wonder if he had a skinny girlfriend? (Sorry, but this doctor was a HUGE woman.)
One of the articles said police were examining the financials of the medical practice. They would be looking for anything hinky there.