Did Voldemort kill Petunia & Lily's parents?

[ghinghapuss]

No: HPFGUIDX 80962

I've been confused over Petunia's behaviour since the last book, as 
I'm sure we all have and I can't find a satisfactory solution to why 
she agreed to take in this hated child of a hated sister. A child who 
represents and is a daily reminder of a world that she despises and 
is terrified of unless there is a huge benefit for her and her family 
that out-ways the 20 plus years of burden that is Harry Potter to 
her.  I don't agree with the love concurs all theories in Petunia 
Dursley's case.   

So I've come up with a theory which popped in to my head after 
reading the essay entitled The Tragedy of Petunia Dursley by Ali 
Hewison on the Lexicon.  I found this to be very interesting and 
recommend the essay to everyone, however while I agree wholeheartedly 
on the idea that Petunia has made a deal with Dumbledore, I disagree 
with Dudley having magical ability. (Read the essay for more detail)

I propose the deal went something like this:  In return for Harry's 
protection, Dumbledore has provided protection for Petunia and her 
family (and of course to Harry as well) from Voldemort, his DE's as 
well as any contact with the Wizarding World.  Why?  I'm thinking 
perhaps Voldemort was responsible for Lily and Petunias parent's 
death. 

I am going to assume Harry's maternal grandparents are dead, as Harry 
and Dudley have never seen or met them in their 15 years of life. 
(That we are aware of up to now.)  Petunia has never spoken of them 
in any of the books and Harry has never asked about them, which is 
strange, don't you think?  My only answer is that they are dead or at 
least severely estranged from Petunia and her family, but if that is 
the case surely they would have shown some interest in their 
grandchildren and at least tried to contact Harry at school?  So I'm 
going with the deceased option for now.  So how did they die?  Well, 
we know Lily and James defied Voldemort 3 times. We don't yet know 
what Voldemort did, but I bet it was nasty and I'm willing to bet one 
of those times Voldemort and/or his DE's used Petunia and Lily's 
parents as bate. 

This to me is a terrifying reality for Petunia, fueling her hate for 
her sister and the WW in general and putting her in a position 
Dumbledore knows is to his advantage.  Dumbledore has to get Pertunia 
to agree to take in this child, who I believe she could easily have 
let die, because Dumbledore needs Harry to live with a blood 
relative. This connection would be meaningless to Petunia but if she 
had known of, or seen her parents death (possibly at the hands of 
Dementors???  She seems to know what they are clear enough) she could 
prove willing to look after this kid in return for the protection of 
her own son.

What do you all think?

Mandy