The Woman in Green (1945)
While talking about the murder and the woman Walter was with, a cop says "And you say the woman was in green?" Then he says "I know; this is a case for Scotland Yard" . In "The Woman in Green", Scotland Yard looks for a woman they suspect of killing someone.
George says "Hey, it's a thingie! A fiendish thingie!" , a deliberate misquote of Dr. Watson saying "A finger! A human finger!"