Potion in the Cave

[Gopal B]

No: HPFGUIDX 145729

Hi,

I have seen many emails that mention the potion in the
cave is Voldemort's potion/ memories/ dark magic. How
is Harry to continue in the quest for the horcrux?

We can think of two different possibilities on the
cave horcrux.

1) Voldemort placed the horcrux there himself (seems
like the kinda thing LV would do). R.A.B found out the
location and took the horcrux much like
Dumbledore-Harry.

2) Voldemort asked R.A.B to put the horcrux in the
cave and R.A.B did everything else but put the horcrux
there.

In either case, LV would not know the horcrux to be
missing unless a) he checked the cave or b) someone
with R.A.B spilled the beans.

In scenario 1), the potion would be filled by R.A.B
with the intent to 'kill'/damage LV and was not meant
for Dumbledore-Harry. This is again because the potion
did not fill itself after Dumbledore consumed it. If
it was RAB's potion then it would be 100% poisonous
and going by AD's reaction it probably was.

In scenario 2), the potion can be LV's dark magic.
Given that horcrux is a precious thing to LV, lesser
probability that 2) would be true. 

So the key questions are:
1) How did LV know of the missing horcrux and R.A.B's
treason? 2) Did LV get back the horcrux or not?
apparently he did not, why did he not try to get it
back? did he make one extra?
3) who put the potion in the cave and what did it do
to Dumbledore? 

Guess the wizarding world is less logical than we
think and we might have a completely different start
for the horcrux hunt.

Gopal.