Detectives arrested the son of a 100-year-old woman today after she was found stabbed to death at her home.
The victim suffered a fatal knife wound to her neck at the property in Hainton Close, Whitechapel, east London.
Police and paramedics were called shortly before 10am today but were unable to save her life.
The Metropolitan Police said a 61-year-old man was arrested and will be questioned over the attack.
It is understood he is the son of the victim and may be suffering mental health issues.
A police spokesman said: "Next of kin have been informed. We await formal identification of the victim.
"A post-mortem examination will take place in due course. A 61-year-old man has been arrested and is currently in custody."