The ninth Dr Kang story, the third in the series "The return of Dr Kang".
Dr Kang is called in by Senor Casales. Somebody in his house is damaging his art works, and has now slashed a valuable painting. Is it his business associate M. Arbin, his friend Colonel Gomez, or his elder son's fiancée Maria Lamiella? Dr. Kang sets a trap for the next night; he will sprinkle blue pigment at the entrance to the living room and see if anyone treads it back to their bedroom. In whose bedroom will it be found?
Glasgow Evening Citizen, 19th December 1956.