I noticed this oddity from PR's 1998 interview. She is describing her first encounter (in her version of events) with the ransom note the morning of the 26th:
17 PATSY RAMSEY: I read -- I read
18 down to about, it says, "at this time we have
19 your daughter in our possession."
20 For some reason, I don't -- don't
21 ask me why but, I start --
22 TRIP DeMUTH: Don't count on him
23 not asking you why.
24 PATSY RAMSEY: I, my first flash
25 that was in my head was I thought it was Beth,
0034
1 our daughter, I don't know why I thought --
2 (INAUDIBLE), and then "daughter in our
3 possession, she is safe from harm, your daughter
4 in 1997," then when I realized this was now,
5 this was new material, this was not something --
6 you know, papers from that had to do with Beth.
7 And just I stopped and just went up the stairs.
Two things. First, a Freudian slip of sorts -- "new material." Why would this be "new material" -- a stand-up talks about having "new material," for example when trying out a joke for the first time. If this ransom note was PR "trying out" something untested, something designed to provoke a particular response, we see why she'd refer to it as "new material."
Second, why in God's name would she think these were papers to do with Beth? Beth was killed in a car accident years before. Why would she imagine a "small foreign faction" would tell her to "listen carefully!" about her late step daughter? Did she really think that someone had dug up Beth's remains and left a note on her back stairs?
But people say things for a reason. There has to be some reason she chooses to introduce Beth here. My theory: this is a sensitive area for Patsy (because she knows she's lying) and in a subtle way she is reminding the police that "We had already lost a daughter -- we have suffered enough -- please don't question me too intensely, I'm a fragile woman."
And tragically, when I read that transcript I see time and time the interrogators letting her off the hook. I think a great psychologically-minded interrogator could have trapped her and gotten her to crack.