Pamela K. Davis was shot and killed during the day inside her home in Costa Mesa, CA (Orange County) on Sept. 10, 1976.

I wouldn’t have otherwise put it in this forum if I didn’t think the sketch from three witnesses (sketch below) looked similar to the familiar Z-sketch.

It was common look back then and his hair’s a tad long (as opposed to the "crew-cut"), but add the similarity with the apparent randomness of the Z’s MO…

From the Daily Pilot, Nov 2010:

Davis, 28, was the new mother of a baby. She and her husband lived in the 2800 block of Velasco Lane, and were trying to sell their house. It was foggy and drizzly on Sept. 10, 1976, when a man wearing thick, black-rimmed glasses with thick lenses and a three-quarter length overcoat, and whose hair was nicely combed, entered the Davis home. Only the woman and a little boy, who was her relative, were in the house, police said.

There’s no evidence that the man broke in, as Davis was showing the single-story house to prospective buyers, police said. It’s possible that he used a ruse to get inside, authorities said.

Relying on evidence and the child’s account, police said the man shot Davis to death in her bedroom. The boy came out of another room when he heard the shots and saw the killer standing in the bedroom doorway, so he ran to a neighbor’s house and called police. There was no 9-1-1 back then.

Detectives canvassed the area and found only two other witnesses: a pair of juveniles who had seen the killer approach the house. Police described the killer as a 27-year-old white man, 6 feet tall with a thin build, short black hair parted to the left with short sideburns, a pale complexion and dark trousers and shoes.

No one saw the killer leave.