text: Shana Grice ended her relationship with "obsessed" Michael Lane who stalked her when she started up a new relationship, Lewes Crown Court has heard.
  The 19-year-old's body was discovered with her throat slit in her bedroom, which had been set alight, in August.
  Mr Lane denies murder.
  Giving evidence, his friend Natalie Fines said she bumped into him during an evening out with her parents on Saturday, 20 August.
  Ms Fines told the court: "He told me she'd dumped him and gone back to her ex. He wasn't very happy about it, he told me he was depressed.
  "As we were all leaving and hugging goodbye, he whispered in my ear 'she'll pay for what she's done'."
  During cross-examination by Simon Russell Flint QC, defending, she added: "I didn't think that much of it. He'd often say things like that.
  "For example, that he'd kill himself, and do it that night, but he didn't act on it."
  The trial has previously heard Mr Lane, of Thornhill Rise, Portslade, East Sussex, put a tracker device on Miss Grice's car after hearing about her rekindling of the relationship with Ashley Cooke.
  He was also cautioned by police after he stole a key to her back door before letting himself into her bedroom in Chrisdory Road, Portslade, to watch her sleep.
  The trial continues.
target: The man accused of murdering his ex-girlfriend whispered to a friend "she'll pay for what she's done" five days before she was killed, a court heard.