Yep.
I guess the parents either didn't see it or just decided to ignore it. Jealousy is self destructive, fed by his parents focus on their daughter.
The father, John Ramsey, had a 22 year old daughter by his first marriage that was killed in an auto accident in 1992. Then his other daughter, JonBenet, was tragically killed.
The speculation I heard on the local talk radio this morning was that John was faced with losing his third and last child, the 9 year old son, to the authorities if it was discovered that the son did indeed kill JonBenet. So he and the wife chose to save him by lying to the authorities.........