A teenager from Hastings denied murdering a woman from St Leonards when he appeared in court by video link on Monday (18 December).
The 18-year-old entered a plea of not guilty to the murder of Ann Scott but pleaded guilty to manslaughter.
He was 17 at the time of the killing, on Wednesday 11 January, and was arraigned – or formally charged – at Lewes Crown Court on Monday after being found fit to plead.
Alan Kent, defending, indicated that his client had pleaded guilty to manslaughter on the ground of diminished responsibility.
Mrs Scott, who was in her fifties, was killed at her home in Hollington Old Lane, St Leonards.
Judge Christine Laing told the defendant: “It is my firm intention to deal with you by way of a hospital order but first I have to hear the facts of the case.”
The judge asked Sarah Jones, prosecuting, to produce an “opening note” containing the facts of the case and the considerations that should be taken into account when sentencing.
The sentencing hearing is due to take place on Friday 23 February.
At the time of the killing, Sussex Police said that officers responded to a report of concern for a person at a property in Hollington Old Lane, St Leonards, at around 6.08pm on Wednesday 11 January.
The force said that the defendant was arrested at the scene and subsequently charged with murder.
Police said that the boy and the woman were known to each other and that officers were not seeking anyone else in connection with the incident.
Separately, an inquest is due to be held into the death of Mrs Scott although no date for a hearing has yet been set.