Not sure if this has been discussed previously, but my thoughts today are on SW's shallow grave and on the bed sheet that was found near her grave.
My thoughts are that CW would have been familiar with oil storage tanks and the size of the openings on these tanks. Did CW want SW's body to be found and did he leave the bed sheet behind to aid in finding her body?
JMO - I do think CW planned everything in advance and like Scott Peterson, I don't think CW ever dreamed that LE would look at him with suspicious eyes because he is such an upstanding guy.
JMO - could CW's plan have been for LE to come to the conclusion that SW and the girls were abducted from their home by a kidnapper? This would explain why SW's keys, cellphone and car were still there.
JMO - could CW's plan have been for SW's body to be found and he left the bed sheet behind to aid in this discovery?
JMO - could it be the girls were put in the oil storage tanks because CW didn't think LE would think of looking there, but would rather be looking for two kidnapped little girls?
To me, this would explain why the bed sheet was left behind and why SW's keys, cell phone and car were left behind. If LE believed this to be an abduction/kidnapping that originated in the family home, finding a bed sheet from the home where SW's body was found in a shallow grave would point to a kidnapper having taken the bed sheet from the home. JMO. And SW's keys, cell phone and car being at the house would also point to an abduction.
JMO - SW's friend, N, raising an early alarm may have prevented CW from getting rid of the kitchen garbage that contained the sheet and pillow cases. After LE was involved, CW would have had a hard time disposing of that.
JMO - my thoughts are what really got him was the neighbor's security cam that showed that SW and the girls never left the house that day and that no one had been to the house. In one of the interviews, CW did speculate they could have left by the back door, where there were no security cams. But with a 6 foot tall fence in back with no gate, LE would not buy that theory. JMO.
JMO - I don't think CW realized the neighbor's security cam recorded the front of his house. I think after that was pointed out to him by LE, he brought up the "emotional conversation" to try to steer LE into thinking SW and the girls may have left on their own and just disappeared.
All speculation, and all JMO.