Police were called at 4.10pm on Sunday, 29 October, to a report of a woman deceased at a residential address in Ash Tree Way, Croydon.
Officers attended along with ambulance colleagues. A 19-year-old woman was found suffering stab injuries and she was pronounced dead at the scene. A post-mortem examination will be arranged in due course.
A neighbour who asked not to be named said the man was pulled out the property covered in blood.
The woman is believed to be an Indian national who is thought to have arrived in the United Kingdom relatively recently. Officers are working to trace and inform her family.
A 23-year-old man was arrested at the scene on suspicion of murder. He has been taken to hospital suffering a minor head injury.
The man and woman were known to each other. At this stage, nobody else is sought in connection with the murder investigation.
Anyone with information that may assist the investigation, including anyone who saw or heard a disturbance on Sunday afternoon at the address in Ash Tree Way, is asked to call police on 101 quoting reference 4546/29oct.
