A follower and confidant of Mirza Ghulam Ahmad who parted ways when the Mirza was gradually leading his community away from Islam.
Mirza calls him Kafir
In 1906, MGAQ wrote a letter to Dr. Abdul Hakim Khan, wherein he wrote the following and the old version of Tadhkirah (2004 edition) had included it as an ilhaam on page 346:
"God almighty has conveyed it to me that every person to whom my call is conveyed and who does not accept me is not a Muslim and is accountable to God for his defult (Letter addressed to Dr. Abdul Hakeem)(April 1906)."
In 1907, MGAQ denied ever writing this. See Haqeeqat-ul-Wahi, p. 178. Here is what he wrote:
"Dr Abdul Hakim in his pamphlet Masih al-Dajjal and other writings accuses me of having written that anyone who does not believe in me, even if he has not heard my name or is living in a country beyond the reach of my call, is an unbeliever and shall go to hell. This is a patent fabrication by the Doctor. I have never said so in any book or poster of mine. It is binding on him to produce such writings of mine in which I have said so"
However, 4 years later in 1911, Mahmud Ahmad authenticated the story of Dr. Abdul Hakim Khan and proved that MGAQ lied when he made the statement in Haqiqatul Wahy. Mahmud Ahmad produced the letter of MGAQ and began his campaign of calling Muslims as Kafirs.
( http://www.alislam.org/urdu/au/AU1-9.pdf (page 316) ). (thanks to xiaahmed)
On Relationship with Muslims
He once wrote, asking for clarifications on relationship with Muslims, and the Mirza replied:
"If you are worried by the question -- how can it be that the multitudes who are not members of our Community have no righteous persons among them -- then, pursuing the same trend of thought you might also ask whether millions of Jews and Christians who reject the truth of Islam have no righteous persons among them. At any rate, when God has been pleased to reveal it to me that every person who has heard my call and failed to accept my claim, is not to be considered a Muslim, and is answerable before God for it -- then under the circumstances, how can it be that I should overlook this Divine command at the instance of a person whose heart is enwrapped in a thousand shrouds of darkness? It is better that I should cut off such a person from the body of my Jama'at. Accordingly, I hereby and from to-day excommunicate you from my Jama'at." (Truth about the Split, 2007, p.283).
Commentary on Quran
Abdul Hakim Khan wrote a commentary of the Holy Quran as well. The references to Abdul Hakim's translation and commentary:
"Abdul Hakim Khan, M.B., has just published an English translation of the Holy Quran with brief commentary in the form of footnotes. It is the first attempt of a Muhammadan at an English-translation and must receive encouragement from the English-knowing Muhammadan public. There exist already several translations of the Holy Quran by Christian writers who have added, wherever they had an opportunity, noted which could throw discredit on Islam. The chief superiority of Abdul Hakim Khan's translation is its freedom from such notes. His notes are generally taken from authentic traditions or reliable commentaries.
Besides this the translation has many new features helpful to a reader of the Holy Quran. It can be had from the author at Patiala for Rs. 5.8a., bound in cloth, which for over 900 pages of printed matter is a moderate price"