In cheerless offices overlooking an immigration detention centre in Bavaria, a group of extremely patient people have spent the past 16 years doing the world's most difficult jigsaw.
They are Referat AR 4 Projektgruppe Manuelle Rekonstruktion, and their life's work is to foil attempts made by the East German secret police in their dying days to destroy the enormous archives they had built up during their 39 years of existence.
Sitting alone in one office last week was Sybilla Reichert, brightening up the bland surroundings in a pink top. On her desk was a pile of torn-up bits of paper, gloves, a set of tweezers, acid-free mending tape and a Ferrero Rocher for later.
"Today I am piecing together the story of a West German family who made a visit to the East," she said.
"This is a record of how they were put under surveillance as they made their way across the border and took a bus to Jena. I've had a lot of these recently," she said, "people visiting the GDR for weddings and birthdays."
Two doors down, Anja Kräker was taping together an architectural plan she had found in the sack by her desk.
"I don't know what it is exactly," she said. "I don't even read them usually. I just like the challenge. I've always been into arts and crafts."
These women are just two of 1,800 people still employed by the German government to work with the files the Ministerium für Staatssicherheit (Stasi) left behind when the Berlin Wall came crashing down in 1989.
Twenty years since two Germanys became one, the ghosts of the divided past still loom large.
The reunified German government recently promised to fund the archives until 2019, and each month 5,000 people still ask to see their own files.
A total of 2.75m requests have been made to view files since the 1991 Stasi Records Act was passed, which allowed controlled access to the archives.
"I'm not surprised that so many people are only now asking to see their files," said Roland Jahn, who on Monday becomes the new federal commissioner for the Stasi files.
"A lot of people were too frightened in the early days.
"They were afraid that they would find out that they were betrayed by their friends and family. But now they are finding that their children, or perhaps their grandchildren, are asking 'What did you do in the GDR? Were you a victim or a perpetrator?'"
Though he has worked in the archives in Berlin's Alexanderplatz since reunification in 1990, Herbert Ziehm, 64, only decided to look at his own file eight years ago.
"I wasn't even sure there would be a file, and as I had never felt disadvantaged by something the Stasi might have done to me, I concentrated on helping those who did.
"So when I requested my file and found that there wasn't just an index card, but 50 pieces of paper and numerous photos taken secretly of me and my family, I was shocked."
In Zirndorf, near Nuremberg, Reichert and Kräker are part of a 10-strong team who are working full-time on an extraordinary project to piece together 15,500 sacks full of ripped-up bits of paper, each scrap a part of a file kept by the Stasi on its people and enemies. When it became clear that the iron curtain was being torn aside, the Stasi tried to destroy its files. Initially, they used a particularly fiendish kind of shredder that used steam to turn shreds into unreadable mush.
But when the shredders broke, the officers used their bare hands to rip up the files they had spent so many years painstakingly compiling.
Such is the scale of the material the Stasi left behind – 111km of paper stored spine to spine, as well as more than 1.4m photos, videos and audio recordings and an astonishing 39m index cards – that the authorities recently admitted they haven't even read half of the files themselves yet.
In Zirndorf the so-called "puzzlers" have managed to piece together the contents of just 500 sacks – around a million pieces of paper – since 1995.
For how much longer they will do so is questionable.
The current crop of puzzlers only have contracts until December and last week in Berlin, Jahn suggested the half a million or so euros spent on manual reconstruction each year might be better invested elsewhere.
"Perhaps we should spend money on personnel working with the files we already have compiled," he said in Berlin.
"People still wait far too long, often two years, to see their files, and that is simply not good enough."
Almost four years ago, a new computer system was unveiled by Berlin's Fraunhofer Institute which, its designers boasted, could piece together all 15,500 sacks in around five years.
The "unshredder" virtually reconstructs the documents by looking for matching colours, fonts and torn edges.
The plan was that the machine would process the smallest scraps, while the Zirndorf puzzlers, who in the 1990s would sometimes spend months piecing together 90 tiny snippets to form just one page, would concentrate on the "easier" work: files only ripped into quarters or perhaps eighths.
The pilot virtual reconstruction project should have already reported its findings by now, but it has hit some snags, said Andreas Petter, an archivist in Zirndorf.
"For example, the computer did not originally understand holes made in the margin of a document by a hole punch. It thinks there is a section missing and tries to look for it," he said. So far the multimillion-euro machine has processed just 400 sacks.
Many question the value of the reconstruction, but Petter says those who do have a "precarious" relationship with the past.
"Victims of the Stasi have the right to decide whether they want to know what happened to them under the dictatorship. They also have the right to ignore it. But people who say we should throw the sacks into the river Spree and be done with it are trying to prescribe how other people live."
Harald Lettner, one of the Zirndorf puzzlers, said his work was important to give people peace – and in some cases, money. "Because of files I have assembled, former East German citizens have been able to prove that they deserve higher pensions," he said. "Whenever I find a scrap of paper with a victim's name on it, I think of how they will feel when they read their reassembled file."
For Jahn, the work of the archives is essential to maintain the "political hygiene" of Germany. "We can't let people who worked for the Stasi keep quiet and get top jobs while their victims suffer," he said. "I simply won't let it be the case that lying pays."
Almost every week in Germany, some public figure is outed as one of the Stasi's "unofficial collaborators".
This year alone, the office manager of the head of Die Linke (Left) party, Gesine Lötzsch, was named and shamed by Berlin's BZ tabloid, and in February, the head of human resources at the Stasi archives, Lutz Penesch, resigned after it become known he had been recruited by the Stasi at the age of 17. To date, around 50 people still employed by the archive have been found to have worked for the secret police in a previous life.
Though members of the public only have the right to view their own files, reporters and researchers can make requests to view files of ex-Stasi employees.
In practice, this means a lot of journalistic "fishing expeditions" every time anyone gets an important job.
Jahn, who for almost 30 years has worked as a journalist for German state television, says it is his job to ensure that what the Stasi did should not be forgotten, just as Germany should never forget the crimes committed during the Third Reich. "We must continue this duty of remembrance to ensure there is no nostalgia for East Germany."
Victim, now pursuer
There is perhaps no man better qualified to look after the Stasi's mammoth archives than Roland Jahn, who takes over as federal commissioner today.
The 57-year-old from Jena was imprisoned in East Germany for daring to question the regime and was kicked out of the country in 1983. He moved to West Berlin and became a journalist, smuggling cameras into the East to report on life under the dictatorship for the [then] West German state broadcaster ARD.
In 1990, Jahn became the first East German citizen to read his own Stasi file, which incorporated 30 box files documenting every aspect of his life on both sides of the wall. He discovered word-for-word transcripts of phone conversations and surveillance records showing the Stasi followed his eight-year-old daughter to school. "Even now I ask myself: what did they want from her? Did they want to kidnap her?" he said.
Jahn discovered friends had informed on him, and that Erich Mielke, the much-feared Stasi head, had signed the form sanctioning his deportation. A hundred Stasi officers were deployed to ensure his removal ran to plan.
He also found evidence officers had run a smear campaign against him, sending anonymous letters to his friends and family in the GDR describing his treachery.They even made a collage with a thousand Deutschmark note with Jahn's face stuck in the middle of it, telling the recipient that he had taken bribes from the Stasi in return for informing on his loved ones. "They basically said: "Look, he is making a living from your suffering," said Jahn.
Jahn's goal is simple: "I want everyone who co-operated with the Stasi to know that even though it's 21 years since the wall fell, they could still be unmasked."
