Quelle/Source: Schmeh

A Crypto Classic: The YOG’TZE Case

The death of food technician Günter Stoll is undoubtedly one of the most puzzling criminal cases in the history of the Federal Republic. Shortly before his death, Stoll allegedly wrote the letters YOG’TZE on a piece of paper.

German version

First of all, I would like to mention that the ICCH forum, where an interesting talk on the history of cryptology is given every two weeks, now has a web page. Patrick Hayes, a Cipherbrain reader, created it. I think it is extremely well done.



On the new ICCH page you can read, among other things, that George Lasry, also a reader of this blog, will give a talk on Vatican ciphers today at 6 pm (German time). However, the dial-in details are not linked on the site for security reasons. If you want to attend (it’s free), feel free to send me an email. Those who want to attend regularly should subscribe to the Crypto-Collectors mailing list. There you will find the dial-in link two days before each talk.

Also, my next ICCH talk has already been announced. On March 20, 2021, I will give a talk with Jerry McCarthy on the Zschweigert cryptograph.

Quelle/Source: Patent


The YOG’TZE case

Now let’s get to the topic at hand. One of the most read and commented articles in the history of this blog deals with the so-called YOG’TZE case from 1984, which centers on Günther Stoll, an unemployed food technician from Anzhausen in the Siegerland region of North Rhine-Westphalia who was plagued by psychological problems at the time.

Stoll felt persecuted for a long time. On October 25, 1984, in the presence of his wife, he cried out, “Now a light is coming on for me!” He then wrote the six letters YOG’TZE on a piece of paper. He immediately crossed them out again.


Quelle/Source: Schmeh

Afterwards, Stoll went to a local pub. There he collapsed, although he had only drunk a little. At one o’clock in the morning, he rang the bell of an elderly woman who was known to him as very religious. Given the hour of the night, she turned him away.

What happened during the next two hours is not known. At about three o’clock, Stoll was found seriously injured in his car, which had run off the road, on the side of the A45 highway. He was unclothed (the picture below is unfortunately not correct, as it shows the dead man clothed and next to his car).


Stoll died on the way to the hospital. Police found that the victim’s fatal injuries were not from the accident. Instead, Stoll must have been hit by a vehicle at another location and brought to the scene in the passenger seat of his car.


The XY film

By far the most important source for the YOG’TZE case is a segment of the television series “Aktenzeichen XY … ungelöst” from 1985. This film is available in two parts on YouTube. Here is part 1:

And here’s part 2:


The YOG’TZE cryptogram

The most interesting question for Cypherbrain readers is certainly what YOG’TZE means. Apparently, there is no language in the world in which this word occurs. There are numerous other possible explanations for it:

  • When the G is read as 6, you get the word YO6’TZE. YO6TZE is a Romanian radio sign.
  • The apostrophe in the middle of the word matches Dutch car license plates.
  • If YOG’TZE is read upside down, you get 3ZL,90X. What this is supposed to mean, however, is also unclear.
  • TZE stands for an artificial flavoring, which is also used for yogurt (abbreviated YOG). YOG’TZE could therefore be an expression that the food technician Stoll knew by profession.
  • YOG’TZE could stand for the first letters of six words.
  • YOG’TZE could be a coded word. However, the plain text would be unknown in this case.

Unfortunately, Stoll’s original write-up has not been preserved. My readers have pointed out that Stoll’s wife reported this cryptogram only half a year later and that she probably saw it herself only briefly.

It may well be that YOG’TZE is just a meaningless string of letters. People suffering from psychosis often utter or write down nonsensical things. Therefore, the chances of ever being able to decode the sequence of letters YOG’TZE are probably rather small. Many of my readers see it that way, too.


How it might have been

Admittedly, the YOG’TZE case is more interesting than the YOG’TZE cryptogram. Why Stoll was killed and whether it was murder are open questions. I had my (amateurish) thoughts on this and published them in a blog article in 2015. This post was accessed very often and commented 96 times. Even years after it was published, comments were still coming in.

I originally assumed that Stoll was murdered. The fact that his case was presented in “Aktenzeichen XY ungelöst” suggests this. After some thought, however, I changed my mind. Since then, I think an accident is much more likely. As I wrote in the article in 2015, the matter could have played out as follows:

  • Günther Stoll suffered from a psychosis. Possibly drugs were to blame. The fact that Stoll felt constantly persecuted can be easily explained by the psychosis.
  • As seen in the film, Stoll briefly fainted in his local pub. This, too, can be explained by psychosis.
  • As also seen in the film, Stoll sought out an elderly woman at 1 a.m. to talk to her. Such behavior should also not be too surprising in a psychosis.
  • Afterwards, Stoll drove his car in the middle of the night to a place close to where he later found her. Wandering aimlessly is common behavior for someone suffering from psychosis.
  • Somewhere Stoll stopped, stripped naked, and wandered around. Again, this undressing is not uncommon in such a clinical picture.
  • While he was walking around, Stoll was hit by a car. Perhaps he was suffering from a delusion and believed he had to jump in front of the car or be able to stop it. This can also be explained by psychosis.
  • The driver of the crashed car tried to take Stoll to the nearest hospital or doctor. Since there were no cell phones at that time that could have been used to get help, there was hardly any alternative to such behavior.
  • The driver of the car involved in the accident did not use his own car to transport the seriously injured man, but Stoll’s VW Golf. There were many possible reasons for this. Possibly the accident car was damaged from the collision. Or it was too small (sports car) for transporting the injured. Or it was packed full. Or the driver had something illegal (drugs?) loaded. Or the driver didn’t want to soil his car with blood. It is also conceivable that there was a second person in the crashed car who did not go to the hospital with him and instead drove on in the crashed car. Perhaps Stoll was still conscious and pointed out himself that his Golf was nearby.
  • On the way to the hospital Stoll’s car crashed. The driver of the latter got scared (probably he was to blame for this second accident, and maybe he was intoxicated) and ran away.
  • Possibly the driver who fled is identical with the hitchhiker who, according to the XY film, was seen that night not far from where Stoll was found.

This presumed sequence of events was already nothing new at that time and is, of course, only a hypothesis. It also presupposes that the XY-film correctly represents the events (this is by no means self-evident, since the police often conceal or misrepresent things for investigative tactical reasons). All in all, an accident seems more likely to me than a murder.


Another hypothesis

Blog reader “elli” suggested another course of events:

I think the most likely hypotheses in the HOBBY-ERMITTLER-TEAM about this case. Key point: The marriage was no longer good. When Günther (G) still left after 23.00 o’clock, his wife was not enthusiastic. She had a black eye at the funeral. It might not have gone therefore peacefully. She locked the door behind G; he should see where he stayed. When G wanted to go in again at home after the papillon, it was not possible. Then he thought about it and tried to stay with the old lady. That didn’t work, and he drove to a rest area near Hagen, which he knew and where he had been several times before. There was a special nightlife there at night, a kind of cruiser-prostitution-homosex scene, maybe drug deals. The place was under firm rule and control. Not everyone was wanted. G was there at times but was rejected and treated unkindly. These were rough guys who were in charge there. Whether G was looking for sex contacts there, whether it was about drugs, or both, remains open. G had taken off his clothes there; that suited the scene. But he had already been warned several times that he was not wanted there. Now they were serious about the threats G feared. He was deliberately rolled over there in the square. But they had to take him away, because they didn’t want any police investigation on that square, not to endanger the night business. The scene apparently represented a lucrative, because controlled and safe, business among selected people. So G was taken to the highway, seriously injured, and left there to his fate. Thus no accident m.E.

This variant also sounds plausible to me.


More on the topic

In 2014, I published an article on FOCUS Online about the case. In the meantime, another article on the subject has appeared in the same place. In it, Ulrich Kayser, head of the Hagen CID, which is responsible for the case, is quoted as saying, “The case is closed, there are no leads. The chances of solving the case are zero.”

I’m surprised by Kayser’s statement, because Commissioner Coincidence is not to be underestimated. In addition, one learns in every second XY program (I have been a regular viewer for 35 years) that many an unpunished criminal cannot withstand the psychological pressure and therefore confides in someone at some point. This can be a friend, but also a random acquaintance. So maybe there are people who know more and report this to the police at some point. So I wouldn’t bet on the fact that the last word has already been spoken here.

And here are two more articles on the subject:

The two articles come from the (unofficial) XY Blog by Kurt Wolfgang Schmidt. There you can always read the latest news about this TV show. The book “Aktenzeichen XY …ungelöst – Kriminalität, Kontroverse, Kult” is also well worth reading.

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Further reading: Codeknacker auf Verbrecherjagd – Schnelldurchlauf

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