We're talking about some pretty slim threads, certainly nothing that strongly points in one direction, or the other. But I've come around a little on the idea that Z may have "interacted" with his victims.
Looking over everything I know it's tempting to try and make those connections, I understand that. But instead of imagining a killer targeting friends over feuds, instead picture a serial killer who likes to stalk his victims. Maybe this killer likes to spend a little more time stalking, maybe there are certain physical features he likes to target, maybe certain personality traits. Maybe as part of the stalking he really does interact with his targets.
This scenario is not out of line with known serial killers. We often here that serial killers are partly defined by the idea that they pick random targets. In reality victim selection can often be a more detailed process, and stalking is not uncommon. Although its fair to say few interact enough with victims to cause suspicion.
So in the balance do I think it's likely Stine knew Zodiac? No, but that doesn't make it a bad lead. Carol's statement should be taken seriously, not to the point of blind belief. But consider this, when it comes to faulty memory we're often asked to remember things which at the time didn't seem important. But imagine yourself in Carol's shoes, she has the opportunity to speak to one of the top cops in charge of the murder of her brother, perhaps emotions are running a little high, but surely she would hang on every word, clarify every statement and according to Tom she associated the memory with a fact about her brothers habits. That sort of behavior aught to help the details stick.
Then we have Tom, a long time Zodiac researcher, a person who despite some controversy has put in a lot of leg work in the case. Tom has the opportunity to speak to Paul Stine's sister, he's going to be in interview mode, (hell Tom, did you have a pen and notepad?) he's not going to just have some casual conversation, he's going to be concentrating on every detail. Surely both Tom and Carol would get the basic essence of this detail correct. I mean they may not remember every word of the conversation, but this fact is a standout fact, both Carol and Tom zoned in on it mentally, fixated on it, chewed it over. What are the odds that Carol's brain just flat swapped it? Not impossible, in fact its exactly the kind of nasty trick the brain plays.
All in all though I find this particular piece of hearsay to be reasonably credible.
