The third girl - Agatha Christie

Three girls share living in a small apartment in London. The first works as a secretary, the second works in drawing, and the third girl (who came to Poirot asking for help) has disappeared while she thought she was a murderer! After that, Poirot hears rumors about guns, knives, and blood, but no evidence and no tangible traces. And now Poirot must decide: is the girl a criminal, or innocent, or crazy?