4 years passed after the mysterious death of Dian Harlin
on November 1, 1986, he went to a friend's house to borrow some tools for a two-day construction job in San Siemian, twenty-seven miles away. He left that evening and was never seen again.
A few days later, friends found Hugh's pickup truck deserted on the side of the road near Cambria. Several personal possessions were left behind in it, including his glasses, backpack, sleeping bag, and some tins containing tobacco and ragweed pot. Its keys were found on the ground a few feet away. His friends later discovered that a fuel line had been removed from it.
Some people believe Hugh vanished on his own due to guilt about Dian's murder. Some of his friends believe that he may have just left for other reasons. Several people believe he was harmed by Dian's killer. They don't believe that he would have left his truck on the side of the road. What is your theory of what happened after when he tossed his keys down and walked away from his truck what do you believe happened what is your theory do you think he was responsible for his wife's homicide he died from exposure or was he a victim of a serial killer what do you think happened to him.?

My best guess on this one was that Hugh flew off the handle and killed Diana, then a few years later unable to live with the guilt he went off somewhere and took his own life. Seems his alibi and stories were a little inconsistent even though they never had enough evidence to charge him.

I think the odds of him meeting with foul play too are pretty slim. Unless of course it was the same person. But who had a motive to do both of them in and why would they wait several years with Hugh? Unless he suspected someone, just doesn't add up. Hugh and Diane were a simple and eccentric but mostly harmless couple who no one really had any reason to kill. Just doesn't really add up. But Hugh and Diane had a tumultuous relationship at best. He was probably the one with the best motive to kill her.

Of course that's just a guess, no way to know for sure. Nothing whatsoever has surfaced about this case since the broadcast, probably will never know the truth about it.

My best guess on this one was that Hugh flew off the handle and killed Diana, then a few years later unable to live with the guilt he went off somewhere and took his own life. Seems his alibi and stories were a little inconsistent even though they never had enough evidence to charge him.

I think the odds of him meeting with foul play too are pretty slim. Unless of course it was the same person. But who had a motive to do both of them in and why would they wait several years with Hugh? Unless he suspected someone, just doesn't add up. Hugh and Diane were a simple and eccentric but mostly harmless couple who no one really had any reason to kill. Just doesn't really add up. But Hugh and Diane had a tumultuous relationship at best. He was probably the one with the best motive to kill her.

Of course that's just a guess, no way to know for sure. Nothing whatsoever has surfaced about this case since the broadcast, probably will never know the truth about it.

Agreed.

I think he's the best suspect in Diane's death, and it's a pretty reasonable hypothesis that guilt over this led him to commit suicide. Given that he was described as a rather eccentric man and something of a drifter, it's anyone's guess as to where he eventually wound up at the end.

Most likely if he took his life how come there has been no remains from him in the years of His disappearance where are his remains.

I think Hugh may have just wandered off into the wilds and let nature take its toll. But I was perplexed about his glasses..

I found it odd Hugh left his glasses in his car, as I would have thought he would need those if he was going to leave voluntarily. Then I thought; what if he just wanted to let go and go into nature? Glasses would obviously help him so he might have left them to make his struggle a bit more difficult and more likely to end poorly. When you add to the fact that he left behind a backpack and sleeping bag, leaving the glasses makes a bit more sense for this reason.

I also thought that considering how Hugh was, perhaps he left the glasses in the car so that someone could use them? But if they were prescriptions, then they'd likely be of little use to someone else.

My last idea was; what if he needed the glasses for driving? Unsolved Mysteries has him wearing them all the time, but he's only wearing glasses in two photos.

I think the main reason he left his truck was because he didn't want people asking questions if he was to give it away.

And to answer Dresden Doll's question; perhaps animals ate it? Bodies can go on hiding for a while if no one disturbs the right area. Maybe no one poked around in just the right spot. Or maybe Hugh picked a very out of the way place that he knew.

This case is so bizarre. I've gone back and forth over the years. The police ruled Hugh out as a suspect in Dian's murder prior to his disappearance. He also completed a construction project on the day of his disappearance, which seems like an odd thing to do if he was planning on committing suicide later that day. Hugh left Morro Bay to do the construction job in San Simeon, and his abandoned truck was found in Cambria. Look at this (https://www.google.com/maps/dir/Morro+Bay,+California/San+Simeon,+CA/Cambria,+CA/@35.5053364,-121.1597402,11z/data=!3m1!4b1!4m20!4m19!1m5!1m1!1s0x80ece10bb9b5aa93:0xaa1be219c181970c!2m2!1d-120.8499924!2d35.3659445!1m5!1m1!1s0x80ed34b1e68e9b69:0x1acae879f4dfcf06!2m2!1d-121.1893211!2d35.6440143!1m5!1m1!1s0x80ecd77a7b67481f:0xc4fd49cb873a8956!2m2!1d-121.0807468!2d35.5641381!3e0) map. Hugh was about halfway back to Morro Bay before he disappeared. Some of his friends had said that his truck had a faulty engine line, which would cause the truck to stall from time to time. Even the condition of the truck was bizarre. The doors were locked, the windows were rolled up, and the hood was pulled up, but his keys were tossed to the side of the truck. He left behind his glasses, tools, and tobacco.

It's also very bizarre that Hugh was the one to come forward and identify Dian's body. It's odd that he would do this if he was the one responsible for her death. Hugh's truck was found abandoned on the outskirts of a fairly populated city. If he walked into town to make a phone call or get help with his truck, could he have met with foul play in that small window? And if Hugh was responsible for Dian's murder and wanted to disappear, why? He was no longer considered a suspect by law enforcement. I did find this (https://www.sanluisobispo.com/news/local/crime/article39161808.html#:~:text=Dian%20Harlin%2C%20whose%20partially%20decomposed,sergeant%20said%20at%20the%20time.) article interesting. It says that Dian's body was found partially nude and that investigators believed the motive to be sexual. This would almost certainly rule out Hugh, unless he decided to stage her body to throw off investigators. But that seems unlikely due to how eccentric he was. He was angry that the police were even considering it a homicide and insisted that she died from an aneurysm.

Interesting to find out about a possible sexual motive. UM didn’t mention anything like that if I remember correctly.

This case was a favorite of mine. I’ve always leaned slightly towards Hugh not killing Dian, but who knows?

One odd thing is Hugh was missing a thumb and forefinger on one hand, which seems like it would render someone incapable of choking somebody else with a leash. Another thing is Harlin’s supposed hippy, pothead nature makes him hard to imagine as a “crime of passion”-style killer. And he waited four years to kill himself........most guilt ravaged people crack before then. And the possible sexual nature of the murder is unusual for a homicidal husband.

All these weird things could have an answer, though. Maybe Harlin didn’t kill her himself but paid somebody to get rid of her. Maybe he wasn’t a chill hippy and the people who spoke about him in the UM segment were lying, or naive. Maybe mental illness caused him to disappear when he did.

Definitely one of the more murky UM cases. Too bad there isn’t much background info about either of them.

The Dian Harlin/Hugh Harlin case is especially puzzling.

Even if HH killed his wife DH, it doesn't make much sense that - because of this - he would leave his truck & disappear from the face of the earth 4 years later, especially given that he wasn't a suspect at that point. If he had split immediately after DH's death, that would have been more suspicious - but he didn't.

So, I am not convinced that HH had anything to do with his wife DH's death.

It is possible that his truck may have broken down on the side of the road & he walked off to get help - and then, while on foot, met with foul play. Or, maybe he just wandered off somewhere & died of natural causes. If either of those possibilities occurred, however - there's no real good explanation as to why his body wasn't found - unless it was very well hidden/concealed somewhere. Or, as someone else suggested - maybe it was eaten by wild animals.

I did find the UM segment unintentionally amusing, due to the actor that played HH resembling & acting somewhat like Tommy Chong - LOL.

I found a recent article on the case, from just last year in 2019, first I'd seen about it in years:

https://medium.com/true-crime-by-cat-leigh/wife-is-murdered-four-years-later-husband-vanishes-7df39935baa1

The article mostly just rehashes what we already knew, but it did say that the authorities seem to think Hugh was murdered too, by the same person who killed Dian. Not that Hugh murdered her and voluntarily disappeared.

I figured Hugh did it and disappeared, but if the police think they were both murder victims maybe they got good reason to think so, ya never know.

Most likely if he took his life how come there has been no remains from him in the years of His disappearance where are his remains.

Where his truck was found is a literal stone’s throw from Cambria. It’s pretty remote with a lot of rolling hills, cliffs, ocean, and forest. I visited the site where Dian’s body was found by the high school in Morrow Bay (literally next to the fence that separates the track from the beach dunes) and where Hugh’s truck was found about two years ago. The field they show Hugh cross leads into downtown Cambria. I imagine that downtown area has changed much in 35 years but the surrounding area has with homes.

In fact, not far from where his truck was found, I ran across a 1967 utility bed Chevy like Hugh’s. I don’t think it was his but it was very close. Point it, Cambria is a very small remote town with lots of places for a body to be hidden and never found.

Most likely if he took his life how come there has been no remains from him in the years of His disappearance where are his remains.

Remains can remain undiscovered for decades, even forever. Where are Suzy Lamplugh's remains? All these people who go missing in massive national parks etc.

Not sure how there is the thought of a killer murdering her & then randomly killing him four years later-what would be the point? In fact since the general belief is he did it why would you kill the scapegoat?

They had a stormy relationship, it is highly likely he finally snapped after years of her deliberately winding him up & with his mental problems killed her & then tried to start a new life-either unable to cope without her &/or in in conjunction with his mental issues led him to take his own life four years later. That she was found in a state of disrobe is more indicative of an impotent man lashing out after being unable to get it up-possibly he tried to force himself on her during the incident.