The third girl - Agatha Christie

Three girls share a small flat in London. The first works as a secretary, the second works as a painter, and the third girl (who came to Poirot for help) has disappeared and she thinks she is a murderer!

Then Poirot hears rumors of pistols, knives and blood, but no evidence or tangible traces. Now Poirot must decide: is the girl a criminal, innocent or mad?