The police found an injured woman in a cemetery in Dortmund on Tuesday evening.
A witness had previously reported to the officials who claimed to have heard gunshot noises nearby.
The woman was not critically injured and responsive, said a police spokesman.
The police had searched for a perpetrator in the evening without any results.
Dortmund - The spokesman did not initially provide any further details with reference to the ongoing investigations.
The "Ruhr Nachrichten" reported on it beforehand.
dpa