After a video became known showing the killing of an injured deer in a garden pond in the Spreewald, the authorities got involved.
This was reported by the German Press Agency.
The veterinary office of the Oder-Spree district has filed a complaint, said a spokesman for the administration.
It should be checked whether the actions of the hunter correspond to the regulations.
According to the dpa, the organization Peta also filed criminal charges against the man.
The public prosecutor's offices in Frankfurt (Oder) and Cottbus as well as the police department south had not received any reports by Wednesday afternoon.
The Dahme-Spreewald district is examining the case, it said.
A debate had previously broken out as to whether the hunter had violated hunting and animal protection law with his actions.
The animal rights organization Peta, for example, accused him of suffering and killing the animal.
The video, which contains disturbing scenes, circulated on social media days ago.
The man rejected criticism through his lawyer: There was no alternative to killing the deer with a so-called interception knife.
The hunter had been called by a hunting ground owner because a young red deer had been shot, the law firm wrote.
The animal got into the swimming pond and didn't come out itself.
A gunshot was not possible because of onlookers and the neighboring buildings.
The client then released the badly injured deer "legally and legally by stabbing behind the shoulder blade".
Lawyer speaks of "redemption"
According to the letter, the hunter leads so-called tracking teams, specially trained hunting dogs.
According to the state hunting association, these hunters are called out, for example, in the event of accidents involving wild animals or to search for wild animals that were not killed immediately.
Association managing director Kai Hamann announced that he "probably could not find any violation of the animal protection law".
The hunter's Hamburg lawyer said: "Because the rescue of the very badly injured but agile animal from its suffering had to take place under extremely unfavorable circumstances in the garden pond, the scenery can have a frightening effect on people who are inexperienced in hunting and wildlife biology."
The video shows the hunter grabbing and stabbing the animal.
According to the lawyer, he had had the recordings made himself.
dam/dpa