Why Leave Harry at HW at the End of HBP?

[gelite67]

No: HPFGUIDX 148156

"Harry lay curled on the dark grass, clutching his wand and panting; 
somewhere overhead Snape was shouting, "Have your forgotten our 
orders?  Potter belongs to the Dark Lord -- we are to leave him!""  
HBP, US hardback at 603.

I understand that if Snape is really working for the Order (which I 
believe he is) that he would not want to take Harry to LV, but that is 
not what he says.  He says "Have your forgotten our orders? Potter 
belongs to the Dark Lord -- we are to leave him!"

I understand that LV wants to be the one to kill Harry.  What I don't 
understand is why LV wouldn't want them to bring Harry to him, given 
the chance.  Why "must" they leave him????  Why go to all the trouble 
to break into Hogwarts and then leave Harry behind when clearly, they 
could have taken him with them?

Angie