it can't be her, she died in the third before he did..... it was all part of his game as well... do you not remember the third so well? <.< you should go familairize yourself with it if not lol....

but basicly he had a feeling that she didn't really care about 'his work' she just liked getting her rocks off with his types of games.... and she ended up revealing herself to him, right before (i believe) the husband shot her...

then alot more talking, and the husband is outraged, and takes a saw to saw's neck before he knew saw's heart was monitored to the explosive on his wife's neck... and she dies when he dies... becuase he coudln't find it in his heart to forgive (saw or the drunk driver that killed their child)