"We were already informed of the conditions in and around the station as we were arriving at our positions by emotional members of the public with crying and shocked children," a high-ranking police officer wrote in a document seen by Spiegel Online and tabloid Bild.
"On the square outside were several thousand mostly male people of a migrant background who were firing all kinds of fireworks and throwing bottles into the crowd at random."
The police vans were themselves the targets of thrown fireworks as they pulled into their parking spaces, and people immediately rushed to the officers to report thefts, violence and sexual assaults against women.
"Even the appearance of police officers on the scene... didn't hold the masses back from their actions," the report notes.
Women – with or without male companions – were forced to "run a gauntlet... beyond description" of drunken men to reach or leave the station.
Fearing that the situation could get even worse and that the ongoing throwing of fireworks could lead to injury or death, police commanders decided to clear the square outside the station beginning at around 11:30pm.
"State and federal police officers were repeatedly fired on with fireworks and had bottles thrown at them during the clearance," the report read.
Despite fights breaking out between police and people under the influence of both drugs and alcohol, the square was clear by around 12:15am.
'Officers couldn't gain control'
But the chaos around the station continued, with the officer recording "numerous crying and shocked women reporting sexual assaults by several male migrants or groups."
"The officers on the ground couldn't gain control of all of the events, attacks and crimes – there were simply too many at the same time for that to be possible."
At some points officers were too busy even to be able to record crimes people were trying to report.
The report also notes that many of the perpetrators were mocking police throughout the night and saying they knew they would face no consequences for their actions.
Crowds at times prevented officers from reaching people crying out for help and were seen threatening them as they tried to report crimes to the police.
The officer writing the report notes in concluding remarks that "the officers completed the whole deployment in heavy protective equipment and helmets between 9:24pm and 7:30am without losing their motivation" – and that "the chaotic and shaming situation on this New Year's Eve made the police even more determined".
Battle over responsibility