The fine layer of dust everywhere , was the first thing that grabbed the attention . Ten "candidates" sitting in a row , was the second .
They looked around and at one another , confused . The professor wondered what was going on . The inspector smiled . Without warning , four of them began to sneeze .
"Your culprit is number 7 ," the professor turned to the inspector , comprehension dawning , slowly .
"Are you sure ?" he was dubious .
"Absolutely . Smart idea , inspector ," he conceded ."What was the deciding factor ?"
"Three short , sharp bursts of sneezing followed by a long drawn out sigh ! Unforgettable and quite unique , wouldn't you agree ?"