Sometimes what we don’t know isn’t Rocket Science. It’s obvious. Sometimes it’s so obvious we miss it. There are two big contextual clues [besides the premeditated psychology of this crime] that strongly suggest Watts murdered his children before his wife returned home that night.
The second clue involves a throwaway remark from Nichol Kessinger, the last person Watts spoke to before killing his wife [a much under-appreciated, under-estimated and under-reported fact].
Kessinger told CBI Agent Koback that she heard a television blaring loudly in the background during her 111 minute call with him on Sunday night. Since there was no television in the basement, the television was likely the loft lounge or in the main bedroom [although he could also have been the television in the downstairs lounge].
This was very odd behavior for Watts, particularly because his children were such light sleepers. Even pulling the car out from the garage in the morning was liable to wake them up.
This suggests prior to the 21:00 call with Kessinger, the children were already dead which is also – perhaps – what allowed him to make such a long call without any threat of interruption or distraction from their waking up and needing him for any reason.
There is another even stronger indicator that the children were murdered on the 12th, and it shifts the timeline even earlier. Do you know what it is?