Tobias Hollitzer is the head of the Stasi "Runde Ecke" Museum in the eastern German city of Leipzig. A row of sealed jars, each containing a seemingly innocuous yellow dust cloth, forms part of the museum's permanent exhibition. But these jars were part of the East German secret police's collection of scent samples used to keep track of dissidents.

Hollitzer talked to DW-WORLD.DE about the Stasi's collection of people's smells and what he thinks of law enforcement using the method today.

DW-WORLD.DE: Mr. Hollitzer, the East German secret police, the Stasi, collected scent samples. Why?

The Stasi had a whole range of methods and means to try to track down people who said or did anything critical of the East German communist regime. Collecting scent samples was used to try to identify those, for example, who had distributed flyers or who wrote critical graffiti.

How did the Stasi collect these samples?

Specially trained dogs are used to identify people's smells

When they found a piece of graffiti or a flyer then they took a dust cloth, which was usually yellow, and left it for a while lying next to the flyers covered by a protective piece of aluminum foil and then they had their sample. The cloth was then sealed in a pickling jar and stored. If the Stasi later came across a suspect in the process of the investigation, they tried to get a sample from this person as well -- of course, secretly. A trained dog was given the two smells, and if they matched, the Stasi had a concrete name.

How did the Stasi collected samples from people secretly?

They would often invite someone in for a talk with the police or other officials, for example, and undercover Stasi officers pretending to be police officers or an administrative person were usually present at this meeting. And while the person sat on the chair in the office, they would be, without knowing it, impregnating a yellow cloth hidden under the seat. When this fictive visit was over, the Stasi officer would then put the cloth in the pickle jar -- and they had their sample.

Was scent sampling a method developed by the Stasi?

No, it's a well-known police method used in criminal investigations, but even in the GDR it wasn't allowed to be admitted as evidence and that's why the samples were often collected secretly instead of openly. The problem is not with scent profiling as such, but rather with collecting scents as a precautionary measure in case they can eventually be used in the future. This is what the Stasi did -- they had a giant scent register of dissidents. They really tried to have a sample of everyone who potentially could have said something critical of the state

How many samples are we talking about?

The Stasi collected as much information as possible about people

I'm not sure of concrete numbers because in 1989 (when the Berlin Wall fell) the samples were destroyed and they aren't listed in the Stasi files. But just in the Leipzig area, it would have certainly been several thousand.

What do you think of current reports that German police have collected scent samples from activists who could be involved in violence in the lead-up to the G8 summit?

I think it is important to be very clear that the danger of the method is using it without having a concrete crime. Collecting samples on the suspicion that people could protest or offend in the future clearly harks back to Stasi times, when security officials operated without any type of state limitation.

In these times of the so-called war on terror, do you think the German state is going too far in its security activities?

The state has being going too far for a very long time -- it's just that now the issues surrounding the collection of scent samples are making this evident because here in Germany, the Stasi are so strongly associated with this particular method.

If you take a look at what has happened here since Sept 11. with new security laws, then we have to ask the question of how much freedom we want to sacrifice in the name of security. Information such as telephone and Internet data now has to be saved for at least six months. Interior Minister Wolfgang Schäuble is calling for authorities to have access to road toll data, and it is clear that we are on the way to becoming a surveillance state.