Dozens of young people triggered a major police operation with a riot in a Dortmund subway station.
As the officials announced on Sunday, they were alerted by security staff on Thursday evening about rowdy and bottle-throwing youths at the Westfalenhallen stop.
When they arrived at the station, they met 40 to 50 people on a mezzanine level who quickly fled.
At this point, a loud bang could be heard on the lower level of the stop.
It later emerged that someone involved had shot a security agent with a blank gun.
Nobody was injured.
When the police investigated the matter, bottles were thrown at them, but they just missed.
The police finally arrested eight people on suspicion of a serious breach of the peace.
The officials would have had to listen to "further massive insults," they said.
The arrested are eight women and men between the ages of 16 and 24 years.
They are being investigated for serious breach of the peace, insults and threats.