I was not sure then if Inglethorp was the criminal or not, but if he was I reasoned that he would not have the paper on him, but would have hidden it somewhere, and by enlisting the sympathy of the household I could effectually prevent his destroying it. 
It was easy for me to elicit the sympathy of the members of the household.
mnli hypothesis: It was easy for me to elicit the sympathy of the members of the household. premise: I was not sure then if Inglethorp was the criminal or not, but if he was I reasoned that he would not have the paper on him, but would have hidden it somewhere, and by enlisting the sympathy of the household I could effectually prevent his destroying it. 