But it is not that simple.
What if the letter really was never in the envelope? No one saw the letter inside it except for one person claiming it was.
There were few people in that house in the morning. It wasn't just TT and DA. Some friends or neighbors were at home and outside home.
According to what I've read about that morning everybody seems to agree that it happened in the house on Minot and that there was a note.
Note that was either:
A) seen by someone prior to the morning of 24th, without the mention of car and Sears:
a1) on the fridge,
a2) retrieved from the laundry basket,
a3) pinned to the door of the house (pinned how? there is no hole in it)
B) retrieved from the post box on the morning of 24th by:
b1) TT, with no whitnesses,
b2) TT, with unnamed whitnesses,
b3) DA, with no whitnesses,
b4) DA and TT with no whitnesses,
b5) DA and TT with unnamed whitnesses,
C) then delivered:
c1) straight to the A's home,
c2) to the A's home after making a call and being instructed to take it there,
d2) DA and TT
E) without envelope, which was delivered:
e1) straight away by DA who drove back to Minot and showed up back fast with the envelope,
e2) fast, by DA but after a call to TT to notify him that envelope is requested by police,
e3) not so fast, by DA but while detective was still at A's,
e4) not fast at all, at the time she showed up with the envelope hours passed, cop left and she later delivered it to the police station,
e5) by DA and TT in a hurry, to the A's house,
e6) by DA and TT with significant delay, to the A's house,
e7) by TT who "couldn't find it" hours later, to the police station,
e8) by TT who was searching for the envelope till noon of 26th
F) said envelope was addressed:
f1) in pencil,
f2) in pen, actually the letter was in pencil,
f3) in pen, but "Rachel" in upper left corner was added in pencil
G) as Rachel's family saw the note:
g1) TT got suspicious about it's genuinity straight away, cause of "Rachee",
g2) FA said it's not Rachel's handwriting straight away,
g3) FA said that and then TT joined in doubt,
g4) TT expressed doubt and then FA joined in doubt,
g5) were immediately confident that's Rachel's handwriting and she authored it,
g6) but maybe someone forced her to write it,
g7) weeks later noticed that it doesn't look like Rachel's handwriting at all,
H) said note:
h1) didn't fit the envelope,
h2) fitted the envelope,
Oh, I forgot to include that letter was either the only one piece of mail that arrived on that day, or received along with some christmas cards.
And so on... and on... and on... with literally every tiny detail in this.