never had the crime rate that san francisco had on december 20th, 1968, david faraday came to betty lou jensen's house to pick her up for their first date, and they promised her parents that they would return by 11 p.m. david and betty were just typical high school kids back then. betty lou jensen was 16 years old and david faraday was 17 years old. he was a popular young man. betty lou jensen was an art student who showed tremendous talent. they went to a restaurant and spent some time with some friends. >> they were supposed to go to a christmas play, but instead they went to a place where young people parked. >> betty lou and david thought they were alone, but they weren't. we know that they were there at 10:30 another person drove by and saw their car, and again after 11. >> another person drove by and saw their car. so they were out there for quite a while and we don't know exactly when she planned to leave, but she wasn't going to make curfew that night. >> venetia was a safe town. you're not going to think twice about parking at lake herman road. i'd be surprised if they were worried abou

david faraday was shot in the head once, and betty lou jensen was shot in the back five times as she was trying to run away the boy was an eagle scout. >> there's no record of any misbehavior on either one of them. >> if you were at that scene and saw the waste of life and these young kids turn your stomach six and a half months later, the killer returned and targeted another young couple. >> darlene ferrin and michael michaud. drove to blue rock springs park. they parked in the parking lot again, a lover's lane area, and had only been there a few minutes in. a car pulled up behind them. he opened fire through the window of the passenger side and at the hospital, darlene is pronounced dead, but michael miraculously survives. >> we think it is. it appears to us that he is killing just for the thrill. >> just days after the initial communications from the killer, a letter arrived. >> dear editor, this is the zodiac speaking. >> normally, a serial killer gets a name from the police or from the newspapers, but in his case, he came up with his own name. >> it included a cipher that when s