This is Death in Ice Valley, an original podcast series from the BBC World Service and N.K.

Even 47 years on, many witnesses have a vivid recollection of the East-style woman and how old she looked, but looks can be deceiving.

Your age is written in your teeth. I'm Neil McCarthy.

And I'm Mority Graph. This is Episode 8, Case Closed.

Last time former KGB officer, Alexander Vasiliev, gave us his courier theory, which sounds like it could fit.

The East-style woman didn't hang around in one place for long or try to blend in like a spy.

She came and went between European cities and she had meetings with different men, including a naval officer.

She could have been a messenger for a spy organisation. It's plausible.

There's no evidence for her being part of a Norwegian espionage ring, but it's an interesting speculation from somebody with first hand knowledge of the secret world of spies.

Let's return to the science for a while to help us with this case. We'll keep things in Scandinavia.

It's a cold night in Stockholm, within the Swedish capital. And we're in the company of Harald, who's joined us from Norway. Could you introduce him properly?

Yes. Harald Schensfeld from Krippos is with us. He is now the leader of the identity unit at Krippos and he is here bringing two three teas of the Islo woman.

Yes, that's correct. I have three teas with me. To give to the scientist here in Karolinska Institute to try to find out how old was the Islo woman when she died in Norway in 1970.

The very, very exciting thing and the reason for us to be here is that the scientists here in Karolinska, they said hello to themselves and said, we have a method.

We believe we can define the age of the woman exact by looking at her teas with a carbon-14 method, where they look at the level of carbon-14 in her teas.

Then they can say something about her age or exact birth year.

Have you used carbon analysis effectively in any other missing persons cases?

No, we haven't done that before. This is new for us.

Harald, you deal with missing persons cases all the time. What do you make of the Islo woman's case?

Well, I am a police officer, so I have to stick to the objective facts. So it's a very interesting case.

It's very special because there are not many people who are found in the forest burned in Norway.

If it's a suicide, it's a very special way to do it. I don't think we have any similar case.

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