After the death of a 24-year-old on Potsdamer Platz in Berlin-Mitte, the investigators are not assuming a crime.
The police announced on Sunday afternoon.
The responsible murder commission and the public prosecutor's office are now checking whether the man's death was favored by negligent action.
Only a few hours earlier, the police had announced that two construction workers aged 22 and 23 had been questioned and then arrested.
The younger man was already free again, it was said.
The 22-year-old was not directly involved in what happened.
The 23-year-old should also be released on the same day.
According to a police spokesman, the questioning lasted longer for him to be able to finally evaluate what happened on Saturday in the break room.
The 24-year-old was found on Saturday with severe stab wounds in a lounge in the basement of the Sony Center.
Rescue workers had tried unsuccessfully to resuscitate the man on site.
The dead man belonged to a group of construction workers who were busy with interior work.
According to the police, there were no other injuries.