Police have been given more time to question a man arrested on suspicion of murdering a teenage babysitter.
Catherine Wynter (19) was stabbed to death as she looked after her young niece and nephew on Boxing Day.
The body of the teen, also known as Katie, was found by her mother at 8am on December 27.
She had spent Boxing Day night at her sister's house in Borehamwood, Hertfordshire, looking after her two young relatives as a favour for her sibling who was out.
The children, aged three and four, were in the house at the time of the murder but were not injured. It is believed they could hold vital clues about the incident.
A court in Hatfield yesterday granted police more time to question an 18-year-old man from Borehamwood who was arrested on Tuesday evening. They now have until tonight to question him.
A 26-year-old man from Islington, north London who was held on Tuesday in connection with the killing was released without charge on Wednesday.
Both men were known to Miss Wynter, and her sister, but were not direct relatives.