Simply put one of the cast members will be murdered (yes another one). But it could happen in any of the remaining five episodes - it doesn't have to be the final one. Personally, I think it will be, but who knows!
I see now on Spoiler Fix the information it had for the final two episodes has now been moved to episode 15 'In The Zone'.
No additional theories as I've already pondered the fact that either Jenny or DiNozzo will be the one to leave and be killed.