Famous painting

"There is something about that letter，Hastings，that I do notlike......" In spite of myself，his tone impressed me. "You think-what?" He shook his head，and picking up the letter，put it away again in thedesk. "If you really take it seriously，can't you do something?"I asked. "As always，the man of action!But what is there to do?The county policehave seen the letter but they，too，do not take it seriously.There are nofingerprints on it.There are no local clues as to the possible writer." "In fact
"Not instinct，Hastings.Instinct is a bad word.It is my knowledge-myexperience-that tells me that something about that letter is wrong-"Hegesticulated as words failed him，then shook his head again. "I may be making the mountain out of the anthill.In any case there isnothing to be done but wait."