114 stab wounds - the victim may not have had any blood left in her body when she was found.
CS apparently walked straight to Aiden's bedroom after he hopped into the patrol car.
The jeans were "damp", according to the witness when CS took them from his hamper. CS rinsed and scrubbed them. When the witness was told, CS retrieved the jeans from her master bathroom and asked the witness if she could see blood on them. The witness told CS that she could be in trouble for attempting to remove the blood so CS returned the jeans back to her son's room.
The bathroom sink drain tested positive for blood.
I think the killer removed his shoes so he could rinse his jeans in the pond before CS tried to remove more of the blood from them. Something made them "damp" either water from the pond or lots of blood or both.
It is sad that she failed to inform authorities of her actions for if she had, it might imply she was simply curious but by no means was she attempting to alter evidence.
@Ray_of_hope kindly posted the link with the Grand Jury's True Bill for Aiden's arrest. It's interesting reading. Their basis was founded on three matters: Aiden's statements, video evidence and items of evidentiary value from his bedroom.