After watching last nights episode, I have a new theory on who killed Sydney.  The clues were not subtle, but it is one that never crossed my mind until now.  They seem to be playing it up so that the viewer thinks that it is Michael, but I think that it is his wife, Vanessa.

She has had a pretty minor role so far in the show, but I have stated before that she must be pretty hard core to be married to Michael and bare his demon spawn!  She has likely had him tied down longer than any other woman has yet, assuming that they were married before Noah was born.

With David finding the bloody necklace in Michael's car the finger is definitely pointed in that direction, but it would be too simple to be Michael and besides I would like to see him stick around a bit more.

Hopefully we will get to see a bit more of Vanessa and get to know her more.  She has potential, that's for sure!