A police spokesman told Die Welt newspaper on Tuesday that it remained unclear whether the head, discovered on Sunday, was a veiled mafia-style threat, a macabre joke, or a particularly passive-aggressive neighbour's way of protesting about the presence of the baby carriage.
The man told police that he had not received any complaints from neighbours about keeping the pram in the hallway.
The carriage and the blanket inside it were reportedly severely damaged by the large quantity of grease that had leaked out of the head.
The man intends to have the pram cleaned, though he said the blanket was beyond rescue. The cost of the damage incurred was unclear.