Who is Dr. M. P. Kahl from Death in the Long Grass and what is their importance?

Dr. M. P. Kahl took most of the photographs presented in the text. He and Capstick were acquainted in Africa, though the nature and extent of the relationship is not discussed in the text. Kahl provides Capstick with a newspaper article written by Alan Root, wherein, Root describes a hippopotamus attack on himself and his wife. Aside from this brief mention and the photography credits, Kahl is not otherwise considered in the text.