Intro
As I continue to study the earliest biographies on the life of Mirza Ghulam Ahmad, lots of pertinent information is surfacing.  For example, the earliest Ahmadiyya sources purposely don’t give a reason of death, however, in 1915, Farquhar wrote that MGA died of cholera, in fact, all of MGA’s enemies and critics were accusing Ahmadiyya leadership of knowing the cause of death and purposely covering it up.

The Ahmadiya Movement. By H. A. Walter. (“Religious Life of India Series.”)
New York: Oxford University Press, 1918. 185 pages.
Reviewed in article ‘Recent Works on Oriental Religions’ by A. Eustace Haydon, published in The American Journal of Theology, Vol. 24, No. 2 (Apr., 1920), pp. 288-293. Published by: The University of Chicago Press
“The Religious Life of India Series,” of which Mr. H. A. Walter’s book, The Ahmadiya Movement,’is the second volume, is intended to give to all who are interested in India a knowledge of the various existing forms of her religious life. This volume is a fine example of sympathetic interpretation of an alien faith. The author, who, unfortunately for India and scholarship, did not live to see his book through the press, says that he has attempted only to give an unprejudiced, accurate sketch of the Ahmadiya movement “as its founder and his disciples themselves conceived it and, so far as I could, in their own language.”

He was told that MGA died on intestinal trouble
“””His death, caused by intestinal trouble, occurred very suddenly, on May 26th, 1908, in Lahore, whither he had come to attend the conference above mentioned, and to secure some medical assistance for his wife. His enemies made much of the fact that, with all his boasted prophetic knowledge, he should not have foreseen the date of his own death, which, had it accorded with his wishes and plans, would certainly have occurred in Qadian, and at a later period. “The Message of Peace” was read at the conference by Khwajah Kamal-ud-Din, just after the author’s death. Ahmad was buried in an unpretentious tomb in Qadian, which had been previously prepared. “””