Following the major policing operation that prevented a repeat of the 2015 sex attacks, police have set up a working group to find out why so many North African men showed up in Cologne on New Year’s Eve for the second year running.

The inquiry will look into why, one year on from infamous scenes in the city in which hundreds of women were sexually assaulted, well over 1,000 young North Africans chose to visit the New Year’s Eve celebrations in Cologne.

One aspect of the night that authorities are looking into, Police Commissioner Jürgen Mathies told Frankfurter Allgemeine Zeitung, is “why [the North African men] all arrived at the main station at almost the same time” and whether there was an agreement in advance to attend the celebrations in Cologne.

Commentators and politicians have weighed in to interpret the events of the night, in which the deployment of 1,500 officers prevented a rerun of the disaster of a year before but the policing was criticised by some on the left as having used “racial” methods of profiling.

Armin Schuster, security expert in Angela Merkel’s Christian Democratic Union party (CDU), praised the police for being “robust and decisive” in countering threats on New Year’s Eve and said he believes North Africans were “trying to run rings around the German state”.

“The fact that so many people of the same background made their way to Cologne – just like last year – that was a test of strength.”

Without the police’s intervention, women would have been attacked in the same way as last year in Cologne, according to feminist and journalist Alice Schwarzer, who agreed that the men were putting on a “power test” for the authorities.

“Had police not intervened this time … hundreds of women would have been chased out of the public space with sexual violence, and the ‘helpless’ men at their side humiliated again.

“It was about [the events of] 2015, and [these North Africans] wanted to show themselves to the western ‘sluts’, and highlight their men to be European floppy-tailed wimps”.

The feminist added: “That was a power test. A challenge to the state. Because these men, who travelled again on New Year’s Eve, had to know that they would be met with police resistance this time.”

The head of Düsseldorf police’s organised crime division, Dietmar Kneib, said he was shocked by the massive presence of young men from North Africa at New Year celebrations across Germany, and said people “must assume that [they were making] a statement”.

The senior police figure argued that it’s hard to believe the discussion around the mass sex attacks seen in Cologne last year “remained completely unnoticed” in circles of North African migrants in Germany.

“The number of [migrants from North Africa] who arrived [in cities], and the pronounced aggressive general mood [of these men] made me think”, the veteran police figure said, and noted that young North Africans are very well connected to social media, the problem lying not with “Facebook, but with those that we cannot monitor”.