Tanuma was a young policeman and apparently quite close with Shōji Sudō.
Ginga Densetsu Weed
He went to search for a criminal dog breeder with his comrade Shōji. Instead of finding their suspect alive, they found a shack with Hōgen and Genba inside eating a dead human body. The police rushed inside and got attacked by the dogs. Tanuma was killed by the vicious dogs.
Shōji felt very bad and responsible of Tanuma's death as a police veteran. He had wished that Tanuma would marry his daughter at some point.