Snape's mission

[Haggridd]

No: HPFGUIDX 15773

Hello all, I am not new to Harry Potter, although I am new to this 
board.  My screen name was Haggridd on another message board.  I am a 
52 year old OBGYN, reared in NewYork City, and now practicing in 
Louisiana.  I will review as many of the older posts as I can, but as 
for now...

Regarding Snape:
Has anyone considered that the only way for Snape to complete his 
mission would be to use polyjuice potion to disguise himself as Barty 
Crouch, Jr.?  There doesn't seem to be any other reason for the 
author to have kept him alive.  Voldemort can detect all lies.  Snape 
may not, therefore, represent himself as a double-turncoat. 
Voldemort knows Severus's history; he would be caught out.  He must 
find a situation where he would be accepted, and not asked any 
embarassing questions.  The Crouch, Jr. scenario satisfies those 
conditions. None of the Death Eaters knows Crouch, Jr.'s fate.  Even 
Karkaroff, were he to rejoin the Death Eaters, wouldn't have known 
that Crouch, Jr. had impersonated Mad-Eye Moody, let alone that Crouch 
had been the victim of the Dementor's Kiss.

Well I hope that I haven't resurrected some theory already thoroughly 
chewed over.  
Best wishes,
Haggridd