Thanks for the info on DNA. Wasn’t aware of that.
Anyhow, I think Mom did it. Probably had a short temper and struck out when the girl objected to being Mommy’s Barbie doll.
My theory is the boy was jealous of all the attention Jon Benet was getting. She supposedly got a ton of Christmas stuff and he didn’t get something he wanted. The parents knew he did it so all the stupid cover-up fake ransom note and hiding the girl’s body in the basement closet...................