BERLIN — In the aftermath of the fall of the Berlin Wall 30 years ago, East Germany’s secret police frantically tried to destroy millions of documents that laid bare the astounding reach of mass surveillance used to keep an iron grip on citizens.

As shredders that were available jammed or broke down, Stasi officers resorted to tearing the documents by hand, stuffing them into bags to later be burned or pulped. But the effort came to a premature halt when citizens groups stormed and occupied Stasi offices to preserve the evidence.

Three decades later, in the same rooms behind the foreboding gray facade of the former Stasi headquarters, Barbara Poenisch and nine fellow archivists are trying to piece those documents, and the history, back together. 

Poenisch calls it “a big puzzle game.” But at the current rate, there are still decades of work ahead.

The archivists have reconstructed more than 1.5 million pages contained in 500 sacks over the past 20 years. There are still around 15,500 more bags to go, stored in Berlin and sites in eastern Germany.

A single sack can take an archivist as long as a year and a half to reconstruct, depending on how finely the documents are torn. Attempts to speed up the process with digital technology have stalled.

The painstaking work, performed by hand, continues amid controversy over the future of the Stasi files.

The German parliament voted this fall to transfer control of the files to the Federal Archives, with promises to invest in preservation and digitalization. Some historians and former regime opponents have criticized the move, saying it is an attempt to draw a line under history and raising concerns that files will become less accessible.

Every German has the right to view the records that the Ministry for State Security, as the Stasi was officially known, gathered on them. More than 3 million individuals have applied to do so.

The agency used tens of thousands of employees and a vast web of informants to monitor every facet of society, causing many East Germans to live in terror. It kept files on 5.6 million people.

Reconstructed pages from the Stasi files have shed light on the agency’s investigations into a Nazi war criminal and into the peace networks in both East and West Germany. 

For Poenisch it’s a more personal document that sticks in her mind: a letter from a mother who pleaded to authorities to release her jailed son.

Poenisch spreads out paper fragments on a table. The sack she’s been working on is from the Abteilung N, responsible for communication within the state apparatus and with friendly countries. 

A memo from Oct. 1, 1986, reports that the political situation in East Germany is “calm and stable. . . . There have been no significant events in either the economy or transport sector.”

Another memo, from April of the same year, outlines a long-term plan for the Stasi to keep up with technological advances. The goal is to achieve a “uniform, integrated digital intelligence network beyond year 2000.”

For the year 2019, the project to reconstitute the documents is surprisingly low-tech.

There’s precedent for reconstituting shredded documents. In the mid-1980s, Iran pieced together and published intelligence reports and operational accounts that had been put through a shredder as Iranian militant students seized control of the U.S. Embassy in Tehran.

More recently, programmers in California have promoted software that can do what the Iranians were thought to have done by hand.

But the Stasi project does not have the technology to deal with shredded material, said Ute Michalsky, the head of the reconstruction department. 

An “E-puzzler” software program, developed by researchers at Berlin’s Fraunhofer Institute, had sounded promising. It was supposed to match scanned fragments together based on paper color, fonts, shapes and other details. But it turned out to be more time-consuming than the manual effort and has not been used for the past two years. 

The German government has dedicated 2 million euros to enhance the scan technology.

The archivists say they don’t bother trying to piece together material torn into more than eight pieces, even though they may be those the Stasi were more keen to hide. 

“I sometimes have the feeling that they knew exactly what to tear up,” Poenisch said. “Unimportant things only get a single tear, but important things: the more important, the smaller the pieces.”

Poenisch says the laborious work doesn’t get dull. 

“The responsibility is high,” she said. “Every document could be important.” 

William Glucroft in Berlin contributed to this report.