Private school pupil Rowan Thompson was due to appear in court on Wednesday accused of brutally killing Joanna Thompson in Hambledon.
But today it was revealed the 18-year-old had died while being detained at a secure mental health facility.
It is understood the teenager died on Saturday, and his trial has now been cancelled.
Mrs Thompson, 50, was discovered with fatal injuries to her neck at around 12.40pm on July 1 last year.
Her death shocked the tiny village and her son was detained under Section 2 of the Mental Health Act then given multiple assessments by psychiatrists.
It is understood he was being kept at a secure mental health unit in Greater Manchester when he died.
A Crown Prosecution Service spokeswoman today said: ‘The Crown Prosecution Service can confirm that the trial of Rowan Thompson has been vacated due to the death of the defendant.
‘Thompson was being prosecuted for an offence of murder.’
Winchester Crown Court, where Thompson was due to stand trial, said a short hearing will instead take place on Friday.
In June reporting restrictions preventing Thompson from being identified were lifted after he turned 18.
At the time of her death, shocked local residents said mother-of-two Mrs Thompson ‘was a lovely lady’ who enjoyed running.
Among those to speak of their sadness was Caroline Vine, who knew her for years. She said: ‘I feel sick and so sad. She was such a lovely lady.
‘No-one had a bad word to say about her.’
A woman in her 70s, who lived in a nearby property, said: ‘She was very shy, very quiet. That's why no-one really knows what has happened or much about her.
‘It's very sad.’
Hambledon is best known as the Cradle of Cricket due to the formation of one of England's first cricket clubs there in 1750.
It was home to England's leading cricket club from about 1765 until the formation of the MCC in 1787.
Churcher's College in Petersfield, where Thompson studied, was established in the 18th century. Alumni include England and Lions rugby star Tim Rodber.