RAB case is broken - all Aurors please read!

[Ceridwen]

No: HPFGUIDX 153289

Tonks_op
> (Thinks to self
 maybe I will get a promotion for this one!!)

Ceridwen:
Apparently this owl was misdirected:

'Auror Tonks, thank you for your good work and diligence on the 
ongoing case of R.A.B.  This time your idea did not pan out, but you 
put a lot of thought and effort into it and the Department of Magical 
Law Enforcement appreciates your efforts.

'As you have been so diligent in your efforts to crack this case, we 
offer you one extra day off this week.  When you return, you will be 
in charge of Alternate Theories Regarding R.A.B., the Locket, and 
anything else which might shed light on the case.  We have come to an 
impasse and you have demonstrated the willingness and the ability to 
think beyond conventional ideas.'

(me again)
I think that R.A.B. is Regulus, but what's happened to him?  Sirius 
said he was killed shortly after he tried to leave the DEs, supported 
by Lupin's announcement at Harry's b-day party in HBP (Regulus 
managed to evade being killed for just a few days).  But Dumbledore's 
talk with Draco on the Tower has led many to believe that perhaps 
Regulus is still alive and disguised as
Filch
Aberforth
Another character we might have seen

If Regulus is dead (evidence: Grimmauld Place passing to Harry 
uncontested magically) then what did he do with the locket?  Is it 
the locket at GP?  Did he leave some sort of message for DD/Followers 
of the Light in any event?  What can Harry learn from Regulus's 
story? - he has to learn something or it wouldn't have been 
introduced in a book about finding and recognizing clues.

In other words, what is the lesson for Harry in his hunt for the 
Horcruxes?

Ceridwen.