Unabomber: Jacob Tremblay on Entering the Mind of a Serial Killer (Exclusive)

'Unabomber's Jacob Tremblay and Annabelle Wallis chat with ET's Emily Curl about diving into Ted Kaczynski's world for their thrilling new biopic, hitting Netflix on Sept. 25. Jacob reveals what type of research he did to understand the psyche of a serial killer, and shares what questions he still has about Ted after finishing the film. Annabelle gushes about reteaming with her bestie, Russell Crowe, and opens up about 'magical' experience of parenthood, which she just entered alongside her partner, Sebastian Stan. More from Entertainment Tonight:    / @entertainmenttonight   Exclusives from #EntertainmentTonight :    • NEW From Entertainment Tonight