Episode 47 of The Trigan Empire
The Secret Assassin
aka The Assassin
De eerzame moordenaar (Dutch title)
The Honourable Killer (Dutch title, translated)
The Secret Assassin was originally published in 8 installments in issues 653 (20 July 1974) to 660 (7 September 1974) of Look and Learn magazine.
To date it has not been reprinted in English.
Plot summary (Dutch)