Sentence:  The story struck the depressingly familiar note with which true stories ring in the tried ears of experienced policemen....The second note, the high alarum, not so familiar and always important since it <WSD>indicates</WSD> the paramount sin in Man's private calendar, took most of them by surprise although they had been well prepared. 
Meaning of the word marked with <WSD> tags:  To point out; to discover; to direct to a knowledge of; to show; to make known.