Police in Cologne on Monday said they had arrested a 44-year-old man suspected of pushing an off-duty police officer to his death over the Carnival weekend.
The suspect, a German national, has refused to confirm whether he deliberately pushed the police officer between two cars, a reason the public prosecutor pressed for murder charges against him.
The judge did not see any evidence to support the police claims and charged the suspect with manslaughter.
The police are reviewing footage from nearby security cameras for clues.
Carvinal celebrations gone too far?
The 32-year-old policeman was waiting on the tram platform with friends on Friday evening before he was pushed in front of an approaching tram.
Local broadcaster WDR said the victim was wearing a special Carnival costume at the time of the incident.
After the incident, the suspect, a lawyer by profession, is believed to have merged into the crowds that had gathered to celebrate the street Carnival season.
He later came forward as a witness, but was taken into custody after investigators grew suspicious of him.