A teenager was issued with a fixed penalty notice by police for wasting time after complaining about an assault by her ex-boyfriend, who allegedly went on to murder her, a court heard.
Police were called after Michael Lane, 27, pulled 19-year-old Shana Grice's hair and tried to grab her mobile phone last March 24, a jury was told.
Prosecutors said the incident happened as she walked down a road after leaving her home, unhappy that he had turned up unannounced, with her two housemates following a visit to a pub.
Lewes Crown Court heard Lane was spoken to by police and denied Miss Grice's claims, before showing officers messages apparently confirming she wanted to be with him.
In a list of agreed facts read by junior prosecution counsel Amy Packham, no further action was taken against Lane.
She'll pay for what she's done
what Michael Lane is alleged to have said
But jurors heard Miss Grice was issued with a fixed penalty notice for failing to disclose she had been in a relationship with Lane, and for "having caused wasteful employment of police by making a false report".
The month before, Miss Grice complained to police about being stalked by Lane and about her car tyres being deflated.
And on July 9, Lane was cautioned by police and told to stay away from Miss Grice after he stole a back door key from her home and let himself in, before watching her sleeping and leaving, the court heard.
The following day, Miss Grice reported to police receiving around seven calls from a withheld number, including one with heavy breathing, which she said she believed was related to the incident the day before.
Miss Grice was told that there were no further lines of inquiry and that the case would be left on file. Then on July 12, more than a month before she was killed, Miss Grice reported to police being followed by Lane.
Jurors heard police treated the incident as "low risk", but that the investigating officer would be made aware.
On August 25, Lane allegedly waited until Miss Grice was alone in her shared bungalow before letting himself in and slitting her throat and torching her bedroom, in Chrisdory Road in the Mile Oak area of Brighton, East Sussex.
Miss Grice's killer had dismantled the smoke alarm in the hallway and disposed of broken pieces of it under her bed, prosecutors have told jurors.
Her body was found face down on the bed in her smoke-filled room after her concerned colleagues reported she had failed to arrive at work.
Lane, who got to know Miss Grice while they worked at Brighton Fire Alarms, is accused of murdering her after she decided to rekindle a relationship with her ex-boyfriend Ashley Cooke.
Prosecutors claim Lane refused to accept their break-up and decided no-one else could have a relationship with Miss Grice, telling a friend: "She'll pay for what she's done."
Jurors have heard Lane stalked her in the months before the killing, and placed a tracker device on her car.
At the opening of the defence case, Lane was asked directly by his counsel, Simon Russell Flint QC, whether he murdered Miss Grice.
In front of a public gallery packed with friends and relatives of Miss Grice, Lane replied: "No." Lane said he took Miss Grice's back door key and let himself in because he wanted to "find out why we ended so abruptly".
He added: "I just wanted some answers for why the relationship had ended. I thought I shouldn't be there."
Lane denied being responsible for letting down or cutting Miss Grice's tyres or making heavy breathing phone calls to her from a withheld number.
But he admitted leaving a note on Mr Cooke's car which read: "Dear Ash, Shana has and always will cheat on you. Happy New Year."
Lane said he left the note because he claimed Miss Grice had been cheating on Mr Cooke with both himself and another man called Wayne.
Lane also admitted fitting a tracker device to Miss Grice's car about a month before the killing but said he did not know why. Lane, of Portslade, denies murder. The trial continues.