Murder in the Mews: a Hercule Poirot Short Story

In this interesting short story, a young woman appears to have committed suicide while her roommate was away for the weekend. When the roommate returned, she found the upsetting scene, and called the police.

However the lead inspector, our friend Japp, was sufficiently doubtful about the cause of death that he called in the help of Hercule Poirot. Where will the inconsistencies lead?