His 23-year-old brother faces the same charges and will stand trial shortly after his elder sibling. Both deny the charges against them.
Cologne prosecution service received 1,170 complaints following a string of sexual assaults in the city on December 31, 2015, almost half of them for sexual offenses. However, police have only gathered sufficient evidence for one more trial, ARD reported.
"We have 1,100 hours of video footage but poor lighting conditions and the general confusion at the scene has led to very limited success in the investigation," spokesman for the prosecution service Ulrich Bremer said.
Dozens of criminal complaints were also filed in Dusseldorf and Bielefeld. A Dusseldorf court heard its only sexual assault case in relation to New Year’s Eve attacks last month, while Bielefeld police had to suspend their investigation after failing to locate the suspect.