Authorities now say that more than 1,200 women were sexually assaulted across Germany that night, including about 400 in Hamburg and more than 600 in Cologne, by more than 2,000 men. Previous estimates had ranged in the dozens, both for the victims as well as suspects.
About half of the 120 suspects whose identity has been established had come to Germany from a foreign countries within the last years. "There is a connection between the emergence of this phenomenon and the rapid migration in 2015," Holger Münch, president of the German Federal Crime Police Office, told Sueddeutsche Zeitung.
How long did it take for the details to emerge?
Days after the Cologne assaults took place, the city's police chief resigned amid pressure to step down. His critics had not only blamed him for not having prevented the mass attacks, but also for not revealing what had happened quickly enough.
On the day after the assaults, rumors about it were spreading on social media — but officials kept silent about it at first. Media outlets, including the country's public broadcasters, were later accused of collaborating with officials because there was barely any coverage of it.
It was only when officials started to acknowledge the scale of the assaults that special broadcasts were aired and the country tumbled into a shock mode. It took even longer until it became clear that mass assaults had not only taken place in Cologne, but also in other German cities such as Hamburg and Duesseldorf. Authorities say, however, that the assaults were not organized but occurred spontaneously.
What is surprising is that the full scale of the assaults has only become clear more than six months later, and only because a police report was prematurely leaked by three media outlets.
Why was there such a delay?
Critics have accused Cologne's police force and politicians of deliberately refraining from informing the public about the sexual assaults. As information finally started to be disseminated, critics pointed out that police officials refrained from commenting on the nationalities of the suspects.
It is likely that authorities did not want to risk fueling tensions without having certainty over how many refugees or foreign nationals were involved in the assaults. German media outlets usually do not specify the nationalities of suspects. Providing their nationalities would be a violation of the country's press codex — a voluntary set of rules determining how media outlets should operate.
Following the New Year's Eve assaults, police departments vowed to release information on similar assaults quicker in the future. At times, however, this has led to refugees being accused of crimes they did not commit.
The delay in communicating the extent of the New Year's Eve crimes is most likely due to a balancing act between the determination of the Cologne police force to not fuel tensions against refugees and the public expectation to fully reveal what happened that night.
Will all suspects be convicted?
Several trials are ongoing, but only 120 suspects out of more than 2,000 men have so far been identified by police. Authorities say it is unlikely that many more will be found.
One of the main problems for investigators is the country's low CCTV coverage. German CCTV systems are underfunded, partially because the nation is more skeptical of surveillance than most others. There is a historical explanation for this: Eastern Germany's intelligence agency used to spy on hundreds of thousands of citizens, fueling more general fears of being spied on by state authorities.
Moreover, the fact that the full extent of the assaults only became clear after weeks has made it more difficult for investigators to question witnesses or victims. As detailed memories of the night start to fade, the likelihood of more convictions will decrease.
Whereas only four suspects have so far been convicted — two of them last week — others have already been acquitted.
How did Germany react?
The New Year's Eve sexual assaults had a profound impact on the German discourse on immigration and refugees. Up until the beginning of 2016, most German politicians and media outlets had argued in favor of a continued influx of refugees.
The public discourse on immigration has since turned more critical. "We can't rule out that people are coming to our country with certain ideas of women being always submissive," Alexander Hoffmann, a member of the Christian Social Union, told The Washington Post last Thursday — reflecting a widespread sentiment among conservatives in particular.
The assaults shocked Germany's "welcoming culture" for which it had been applauded in the Middle East in 2015. They also increased pressure on Chancellor Angela Merkel to stop the influx, to which she ultimately gave way by pushing for a deal with Turkey. That deal has now helped to significantly decrease the number of refugees coming to Europe this year.
When Germany's parliament, the Bundestag, passed stricter sex assault laws last Thursday, the vote was mainly perceived as a consequence of the New Year's Eve incidents, as well.
Amid a delay in parliamentary action, some took matters into their own hands this year. An eastern German railway company was criticized earlier this year for planning to introduce women-only carriages to convey a general feeling of safety.
"This has nothing to do with sex assaults," a spokesperson was quoted as saying then after being criticized for allegedly exploiting existing tensions.