Apparently Dexter manages to have access to Saxon's computer. If you pause the promo at 0:19 you'll see the names of some of Saxon's victims.
Among the names of Cassie and Zach we also see Deb's name (!!!) such as J. Mitchell's name. Yes, J. Mitchell is obviously Jonah Mitchell, Trinity's son.
What does that mean for Debra? Will Jonah return? Share your theories and predictions in the comments section!