Ivy said:BC, I disagree that the absence of the items indicates that a 5th person was in the house that night. Have you forgotten that John, Patsy, and Burke were not searched when they left the house on the 26th? Patsy could have removed the items all by herself, in her purse. And don't forget Auntie Pam's famous sweep of the house. She could have removed evidence without even knowing it, just by picking up things the Ramseys asked for.
IMO
Ivy, I fully appreciate what you are saying, but the laws of probability have to be considered when there are multiple choices -- all of them possible. It's just not likely a Ramsey had the items on their person when talking with the cops that morning. The items are relatively bulky.
Also, besides the cord and duct tape there are other missing or apparently missing items of evidence. For instance, the murder weapon may be missing; the tip of the paint brush handle is missing; the dark blue cloth used to wipe down the body is missing (which was likely an article of the perp's clothing); the size six panties is missing; the red ink pen used to draw the "heart" is missing; nine pages torn from the notepad from which the ransom note was written are missing; the stun gun is missing; and therefore it can be said the intruder or houseguest likely invited into the house that night (the fifth person), and who took the items with him when he left in the wee hours of the morning, is missing.
JMO