Question about Horcrux?

[honeykissed246]

No: HPFGUIDX 153171

Hello...I am new to the group.  I only recently began reading the 
Harry Potter series and find them quite fascinating.  I did have a 
question about the Horcrux that was in the cave in HBP.  After 
Dumbledore died, Harry retrieved the locket and (I think) it was not 
the real one and that the ACTUAL horcrux had been stolen by R.A.B. 
and a fake one left behind with a note. I immediately began thinking 
that whoever stole the original horcrux out of the cave, either one 
had to be Great at "Potions" (Snape) and detecting "hidden magic" 
because of all the barriers that had to be overcome to actually get 
the locket.  Remember Dumbledore had to drink all the liquid before 
uncovering the locket and then he was not in good condition 
afterwards.  He screamed in pain, needed water, etc. 

Second, remember even Dumbledore said that one person alone could 
not have retrieved the locket and he was grateful that Harry had 
accompanied him.  Now if that is true, did someone accompany R.A.B. 
into the cave to get the orginal horcrux?  I know a lot of people are 
saying that R.A.B. might be Sirius's brother, Regulus Black who was 
killed by Voldemort personally. If this is true, did someone else go 
with him into the cave and thus knows where the original horcrux is. 
I am just not sure and wanted to know what you guys thought.  Again, 
I am new so I am not sure if this has already been discussed but it 
has intrigued me.  Could this be one of the reasons Dumbledore trusts 
Snape?  

"honeykissed246"