Quint from Ain't It Cool News attended a Lionsgate luncheon at ShoWest where actor Tobin Bell (Jigsaw from the SAW movies) announced that production on SAW 4 will begin on April 16th.

It was also revealed during the presentation that Bell will be back for both SAW 4 and SAW 5.

Bell mentioned that he hasn't read the script yet for SAW 4, so he doesn't know anything about the plot.