Identifying the cause of the collapse of Cologne's historic archive on March 3 of last year, is proving to be a major headache for the city. Glaring technical errors discovered on the site strongly suggest that the building work there is to blame for the collapse.
But one year on, no one knows exactly what went wrong and who is responsible.
Cologne's public transport operator KVB, which is building a new underground line in the area, has come under fire. So has Germany's second-biggest construction firm, Bilfinger Berger, which leads the consortium that is in charge of the work.
The city archive was located on top of one of the construction sites, and there are concerns now that other, related sites in the city may be vulnerable too.
Cover-ups and sloppy workmanship
At the end of January, prosecutors started investigating a foreman and several workers for fraud and theft.
Workers admitted to prosecutors that they had stolen a large part of the supporting steel rods that were supposed to prop up the foundations and sold them on as scrap metal.
Though that is most likely not the cause of the collapse, it implies a lack of supervision on the various construction sites of the underground project in Cologne's city center.
Prosecutors are also investigating evidence that legally required control mechanisms were not in place and that documents were faked to suggest regular site checks had taken place. According to the local Koelner Stadtanzeiger daily, a company involved in building wells to ensure stable foundations told police that its workers could not remember a single check being carried out.
The whole underground project has become a symbol for cover-ups and sloppy workmanship. The Koelner described researching the latest developments as being comparable to reading "a report from a banana republic."
Local businesses suffer
It only took a few seconds for the archive to collapse in a heap of rubble last March, but the impact on shopkeepers in the area is still being felt now.
While workers are still trying to retrieve the last 10 percent of historic documents from the rubble, businesses nearby are unhappy about the lack of support in the aftermath of the disaster.
Gerlando Bruno is one of them. He runs a hairdresser's near the collapsed archive site. He says local businesses have not received enough help to cope with the fallout.
"I can't understand why the council keeps sending parking attendants to this area, you'd think they'd want to help the shop owners here, but that isn't happening," he told Deutsche Welle. "They actually punish us. We don't need more parking tickets to be issued here, they should cut us some slack."
It will take decades and up to 400 million euros ($542 million) to restore one of Europe's most precious archives.
Before the collapse, the archive housed 65,000 documents on the history of Cologne, the Rhineland and the Prussian Empire. Some dated back 1,000 years. The archive was known as the 'memory' of Cologne.
Slightly further north, work continues on the same underground line, and there are concerns about this site too. In some places, over 80 percent of supporting steel rods are missing. It is near the Rhine River, so flooding is becoming an issue here. Despite assurances by the construction companies that the site is safe, residents are wary.
"I've not received a lot of information so far," said Huong Zhou, who runs a Vietnamese restaurant opposite the construction site. "There's definitely not a lot of information for residents here and we don't really know who to turn to. It is very disconcerting."
Call for improved legislation
One of the main complaints by politicians and experts is that Cologne's KVB transport company commissioned the work and, at the same time, functioned as chief supervisor of the whole project, at least until the archive collapsed.
According to witness statement, which Deutsche Welle has seen, the project's chief structural engineer for the project, Rolf Sennewald, told police that he had been unaware of any problems on the site. But three months before the archive collapsed tests in the basement showed cracks in the tiles. There were also indications that too much water was seeping into the construction pit below the archive.
Sennewald said these findings should have set alarm bells ringing.
Conflict of interest
He also criticized the KVB for not granting him overall supervision of the project, which, he said, was common practice. But in this case, the KVB hired its own people. Some of the companies involved in the project have said there was in fact no supervision at all.
The local government, a coalition made up of Social Democrats and Greens, is keen to introduce new legislation to change this.
"When it comes to these major transport projects, we must ensure that those commissioning the work cannot at the same time be their own supervisors," said local Green party parliamentarian Joerg Frank. "The law needs to be changed to reflect that. Because all the parties concerned have said what they did wasn't illegal."
Both the KVB and Bilfinger Berger have started their own investigations into why the control mechanisms on the various sites did not work.
Bilfinger's chief executive, Herbert Bodner, a construction engineer himself, has admitted that he is faced with what he described as "criminal activity" in the company. He said it was incomprehensible that the steel rods that support the walls were largely missing.
The KVB has hinted that there may indeed have been problems regarding its supervision of the project.
Author: Nicole Goebel
Editor: Nancy Isenson