A couple parks their car at night in a secluded spot (the woman driver picks the spot) but don't get the chance to fool around as Zodiac shows up in a car that pulls up and parks behind them. The killer then shines a flashlight on them, walks up, and opens fire on them with a handgun, shooting both several times (with very bloody results and seen from several angles).
A couple basks (clothed) by a lake during the day, but the woman becomes concerned when she sees a figure approaching them. It turns out to be Zodiac who's masked and holds a handgun on the two, telling the woman to tie up the man. She does (hands behind the back) and Zodiac then ties her up (pushing her from a kneeling position down to the ground to hog-tie her). He then does the same to the man before proceeding to stab him repeatedly in the back (we don't see the impact, but do see the motion and hear the impact, all in a disturbing fashion). He then does the same to the woman, including then stabbing her in the front of the body, which we do see in graphic detail (although there isn't a great deal of blood then). We later see and hear that the man, although badly wounded, did live.
Zodiac suddenly shoots a cabbie in the neck from the back seat, killing him (with bloody results). When David and William arrive on the scene, the cabbie is partially hanging out of the open door, dead and bloody.
There's a loud and disturbing scream on the phone as Melvin talks to who he thinks is Zodiac.
A woman drives down the road at night with just her infant in the front seat when another car flashes her from behind. She pulls over and the man (whose face we never see) tells her that her right rear wheel is wiggling, and offers to help. She agrees and watches the man (in the side mirror) work on the lug nuts, finish his work, and then leave. She then pulls back onto the road, only to have the car shimmy and that wheel then suddenly come off. The man then returns in his car and offers to give her a ride. As they pass a filling station that she points out, the driver tell her, "Before I kill you, I'm going to throw your baby out the window." The next scene shows the distraught mother by the side of the road, with bloodied hands, all frantic. Others stop to help, and we hear that she jumped out of the moving car, and then see that her baby is okay (she had it hidden).
David, William and Jack interview a potential suspect and become increasingly alarmed (but keep it to themselves) when the clues keep adding up to him being their man (such as wearing a Zodiac brand watch, etc.). After his name is out about him trying to solve the case, Robert gets a call that only features heavy breathing on the other end (a previous signature of Zodiac).
While interviewing a man who knew another person Robert believes is Zodiac, Robert suddenly thinks this man might instead be the killer. Robert reluctantly follows him down into his dimly lit basement, hears sounds from upstairs, and becomes progressively freaked out by the clues pointing to this man. Robert then tries to rush out, but finds the front door locked. That man then unlocks the door and Robert rushes off into the night. When Robert returns home, he finds all of his kids missing and panics, thinking the killer has them, but he then finds a note from Melanie that says she took the kids to her mom's and for him not to call. He then hears the door open and sees the shadow of a figure walking in, but it's just Melanie. Robert goes to see the man he thinks is the killer and just stares at him in the store where that man works