They found plants in his garden and held him for three months while they worked out what to charge him with. He stopped eating. The story went everywhere, and it did more for cannabis in Slovenia than anything he had planned.
He is precise about the geography of the offence.
"In Slovenia, there is a very big difference between city and rural area regarding how they treat cannabis."
He had opened a grow shop in a rural part of the country in 2007, and he knew what that meant.
"If you opened a grow shop in 2007 in the rural areas of Slovenia, you have to know that you will face some challenges, especially with the law."
The challenge, when it came, was about a garden rather than a shop.
"I had a few plants — let's say a few, a lot of plants in my garden."
He was put in a cell while they investigated.
"So they put me in investigation prison, temporary, for three months."
He describes what he did there without dressing it up, and then, in the same breath, what it produced.
"Those were very interesting days, since I started hunger strike and all this. But everything is good for something. So that was the most fruitful time for cannabis in Slovenia regarding media, because the story was everywhere — in newspapers, on television, everywhere."
Then the sentence that explains the twenty years since.
"I'm stubborn."
What he did next was not go quiet. In 2014 he put Slovenia's first scientific cannabis conference into a hotel in Ljubljana, and he got there by default.
"Rick Simpson should actually organise, but they couldn't get the whole organisation under the roof. So I took over and organised that in Ljubljana."
The same year he ran a second one on law and human rights, then took the format to Belgrade and Skopje.
"So the snowball started to roll."
Being at every cannabis conference in Europe gave him a different idea about who needed to be in the room.
"I started to think about how to bring this cannabis knowledge a bit more. And with my colleague from the faculty, we started to organise seminars and education for doctors and nurses."
He is careful about the claim and then makes it anyway.
"That is actually the first official education in Slovenia and one of the first in Europe."
He is not careful at all about how it is going.
"We have maybe 30 to 40 nurses in one seminar, and maybe one — or not even one — doctor or physician."
And he draws the conclusion that follows from it.
"Until even physicians realise that they need to have a click in their heads, it will not be available for patients."
His current obstacle is nine samples and a border.
"I'm now struggling from January to import, officially, nine samples from Iceland. And today we are almost May."
He makes a point of the word officially.
"I could smuggle it, but I didn't want to."
The rule he says is coming next would make the ordinary machinery of science into a crime.
"Even the cooperation between two laboratories can be trafficking of cannabis, which is really stupid. If I send two grams of cannabis to another laboratory to check my work — cross-checking — it can be criminal offence if I don't have all the bacteriology for each and every sample."
"But in science, this is not doable. It's not sustainable."
Then the part that is about money rather than principle, which he raises himself.
"Now I'm struggling for months with nine samples. How much money is this? How many working hours? To whom should I charge this to be profitable as a company, or institute, or laboratory?"
His diagnosis of where the obstacles come from does not blame a lobby.
"I'm sure it's not just the pharma lobby. It must be something else as well. Maybe we want to be more Pope than the Pope itself."
And the line he returns to twice in an hour.
"We can regulate nuclear weapons, whatever. But we are not able to rationally regulate one plant."
The research he is doing now involves sending seeds off the planet.
"Since I got involved in some research in the Faculty of Health Sciences in Ljubljana and some other institutions, opportunity came out to send some seeds to space to see if there will be any genetic changes after we bring them back."
He does not present this as a plan.
"You always go with the flow and you see where you come."
What he does most days is work with sick people, and he is unsentimental about the limits.
"Mostly cancer patients. Autoimmune diseases, epilepsy, Alzheimer's, Parkinson's. But I work mostly with cancer patients."
"Cannabis is not panacea. It doesn't help everybody the same way. But still it is very powerful medicine."
Asked which patient he remembers, he gives an age and a city.
"The youngest patient, from Rijeka. That was back in 2010 or 11. She was born in August and diagnosed with brain cancer in December, with three and a half months."
Then the only part of the answer that matters to him.
"And today she's 14."
Three or four days a week he is with patients and in the laboratory. The rest of the time he is on a small farm with an inventory he clearly enjoys reciting.
"I have chickens, I have a lot of cats. I have a dog, I have hedgehogs, I have crows, I have fishpond."
The working day starts slowly and then stops belonging to him.
"Seven to nine, coffee and crosswords and Sudoku. And then I start to work with the patients, preparing samples for the laboratory."
"I can never actually plan what I will do, because I never know who will call me in five minutes."
His priority order is a sentence long.
"I always adjust my time to sick people. They're first and then everything else. Even the tax office or police. They have to wait."
On the police he starts diplomatically and does not stay there.
"Generally not bad. I don't want to insult police, but they should use a little bit more what they have in their heads. Like brain."
The specific case he cannot get past is not his own.
"You can really not criminally charge sick people in the fourth stage of glioblastoma for growing for themselves. Where is the justice here?"
"It's just harassing people for nothing."
He began at thirteen, in the 1970s, and he says the country he began in was easier than the one that came after.
"The cannabis was actually everywhere. It wasn't that stigmatised then. When I studied in Ljubljana, nobody asked me about cannabis."
The repression, in his account, arrived with independence and a new drug law.
"Cannabis use and cannabis possession was never a criminal offence in Slovenia. Trafficking was. But for the police and prosecutors, it's easy money."
He thinks the public is already ahead of the law, and he cites a number.
"On the referendum it was like 52% in favour of personal use."
Asked what one thing he would change, he does not name a statute.
"To change public opinion about cannabis, based on the misinformation and bad propaganda in the last 70 years. Because this is the only obstacle. A switch in the head."
Asked what nobody is talking about, he names the same seventy years from the other end.
"The unnecessary damage done to the people. Families were ruined. If you go to jail, you lose your job. You lose your business. They can take your kid away."
"For what? For two joints?"
Asked how the future should be, he uses one word.
"Free. That's it."