It's not exactly The Great Escape — considering inmates had internet access and could leave to do errands during the day.

Nevertheless, people in Iceland are wondering how a suspected criminal managed to jump out a prison window and catch a flight to Sweden without anyone noticing — especially the prime minister, who happened to be on the same flight.

Sindri Thor Stefansson was in custody for allegedly being the mastermind behind a heist — in which 600 computers used to mine bitcoin were stolen. And now no one seems to know where he is.

As It Happens guest host Susan Bonner spoke to University of Iceland criminology professor Helgi Gunnlaugsson about the curious case. Here is part of their conversation.

Professor Gunnlaugsson, you were at the prison yesterday. Tell us about this escape.

I just got there like 1 1/2 hours after the prison escape. Actually, it was very quiet and the prison guard did not seem too much alarmed.

You see, this is an open institute, so the prisoners are not really locked and there's no fence around the prison. So, well, then, he decided to leave the prison and it's a surprise to everybody.

A worker walks along a row of computer rigs that run around the clock 'mining' bitcoin inside a cryptocurrency mine in Keflavik, Iceland. (Egill Bjarnason/Associated Press)

But why is the security so lax at this prison?

This is actually used for prisoners who have been serving a long sentence. This is kind of like a bridge out to society to adjust them, to help them integrate into society.

It's an institute where you believe in the person. You trust in the person not to escape. And usually it works very well. It's very unusual that there's a prisoner who escapes from this institute.

For this particular case, this person who escaped, he was in custody. He had been in custody for three months or 2 1/2 months. He had not been sentenced. He had not been convicted.

He was waiting to see his charge in a few days so probably he just wanted to flee before facing the charge, and the eventually sentence, I guess.

What did he do after he escaped from the prison?

Apparently he just went to the international airport and got on a plane to Sweden. And the curious news item about this was that on the same plane we had the prime minister of Iceland.

That's an incredible detail. What's been the reaction to that bit of news?

Everybody is really kind of surprised about the whole thing because this is so unusual for us. First of all, a prison escape is unusual. And then second, a prisoner escape that actually got out of the country — that's almost unheard of.

Usually, when we have a prisoner escape, you will be caught in a matter of a few days. You are just getting drunk with your friends at the local pub downtown ... or something like that, and you'll be brought back to prison. But this case is very different.

Icelandic police have informed their Swedish colleagues that Sindri Thor Stefansson likely fled to Sweden after a prison break. (Reykjavík Metropolitan Police/Associated Press)

Why was he in prison in the first place?

It was because of a burglary. It was a break-in with computers. It was actually one of the major crimes in Iceland in recent years, in the sense of that they were able to get away with 600 computers, specially equipped to deal with bitcoin.

We're not talking about regular computers. We think, here in Iceland, that this must be kind of an international criminal network. This is maybe an inside job. I'm pretty sure people knew what they were doing. And of course, you're not going to be able to sell an item or a computer like that in Iceland.

This is something that probably, maybe already, out of the country. These specially equipped computers are worth millions of dollars. The magnitude of this crime is pretty unusual for Iceland.

Professor Gunnlaugsson says it would be hard to sell the stolen computers in Iceland and that they have probably already been taken out of the country. (Dan Kitwood/Getty Images)

How long do you think it will take before Mr. Stefansson is caught, or will he be caught?

I would expect that he will be caught in a matter of days or weeks, definitely. They will track him down. I'm pretty sure about that. You're not going to be able to disappear like that for a long time.

Do you think they will put him in a more secure prison next time?

I guess with the custody thing, I don't think we will see people in custody in an open institute like that one. I really doubt that is going to happen.

And actually, it is unusual in the past too. This is not a regular procedure for us to have someone in custody in an open institute. So this is a special case.

Written by John McGill. Interview produced by Nathan Swinn. This Q&A was edited for length and clarity.