Article date: Sep 1980
Article title: Dr. Matrix, like Mr. Holmes, comes to an untimely and mysterious end
Mathematical Games column? Y
Book: 4. The Magic Numbers of Dr. Matrix
Chapter: 22. Istanbul
This data confirmed? yes
Notes
Peter Rowlett (5 September 2022):
Peter Rowlett initial guess (Uncertain)
Peter Rowlett (29 October 2023):
I have seen this chapter and column side-by-side and they match.