If memory serves me correctly - there was a party the night before.
I think I remember one theory that perhaps the perp simply hid in the house and waited for everyone to leave, and waited for the family to fall asleep.
He grabs the girl and carries her to the basement.
If he manages to commit the murder without waking anyone, then he does have time to write a weird note.
And if he works with Mr. Ramsey, then he knows the amount of his bonus.
If he is strange enough to commit these acts - he is strange enough to write the note.
I’m not saying I know one way or the other, but one theory is just as strange as the other.
I find it hard to believe parents would mutilate their child’s body instead of calling 911.
The child was not mutilated. She had a skull fracture and was strangled with the garrot. Either the fracture or the strangulation could have caused death.
As for your finding it hard to believe that parents would "mutilate" their children, it happens every day. Somewhere in the world at this very moment, children are being sold into sexual slavery by their parents. Girls are having their external sexual organs brutally removed by their fathers or other male relatives. Plenty of parents do horrible, horrible things to their children.
BTW, strangling a small child with a garrot is a sign of one of two things: Either massive overkill, or a murderer who didn't think he or she had the hand strength to do it without a tool like a garrot.
Given the facts of the case, it is entirely reasonable to be skeptical that the murder was a totally random act committed by a complete stranger to the Ramseys.