Fritz Kunz replaces Höllerer after the latter's retirement to care for his mother. He has been drawn from the statistics section of the force. Initially he is very much out of place in the slightly freer atmosphere of Brandtner's office. A running gag in his early appearances deals with his obsessive-compulsiveness and fussy attention to the placement of his desk stationery (e.g., pencils arranged from tallest to shortest and paper clips aligned) only to have Rex or one of the others move everything around.
Kunz's background in statistics is also often the source of amusement, as he is seemingly able to deliver, from memory, obscure statistical information about the activities of criminals. He tends to be used to man the phones during investigations, rather than on active duty. However, he is also occasionally required to go undercover (once as a kitchen hand, another time as a stable hand and another as an entertainer in a street market), much to his chagrin.
He has two appearances in the Italian series.