A teenager's murder at the hands of an obsessed stalker could have been prevented if police had listened to her fears, her devastated mother has said.

Sharon Grice criticised police for not taking her 19-year-old daughter Shana Grice seriously before she was killed by her jilted ex-boyfriend Michael Lane.

She spoke as Lane, 27, was found guilty at Lewes Crown Court of murdering Miss Grice in the bedroom of the bungalow she shared with two housemates in Brighton last August 25.

In a victim impact statement read in court, Mrs Grice said: "We brought Shana up to respect authority and to always respect the law.

"We firmly believe her murder could have been prevented if her fears had been listened to and taken seriously by the police."

Mrs Grice said the family "instantly" knew Lane was responsible as he had been "harassing and stalking" her for the past year.

Officers received at least four complaints about mechanic Lane's behaviour towards Miss Grice in the months before he fatally slashed her throat.

It emerged at his trial that police were told Lane had pulled Miss Grice's hair and grabbed her mobile phone five months before she was murdered.

No further action was taken against him but Miss Grice received a fixed penalty notice for wasting police time after not disclosing she had been in a relationship with him.

On another occasion, Lane received a police caution after stealing her back-door key and letting himself in to the bungalow she shared with two housemates in Brighton before he watched her sleeping.

The Independent Police Complaints Commission (IPCC) is carrying out an investigation into the contact between Lane, Miss Grice and Sussex Police in the run-up to her killing.

An IPCC spokesman said investigators had already quizzed a number of witnesses and extra interviews would now be held with police officers and staff linked to the case.

The questions for the police emerged as judge Mr Justice Green warned Lane faces life in jail with a "very substantial minimum term" after being found guilty of murdering Miss Grice following a 10-day trial. He will be sentenced on Thursday.

Claps and cheers rang out in court among Miss Grice's friends and family as Lane was convicted after just over two hours of deliberations by jurors.

Lane waited until she was home alone before slitting her throat and torching her room after she decided to rekindle her relationship with ex-boyfriend Ashley Cooke.

The trial heard Lane refused to accept their break-up and decided no-one else could be with her, telling a friend: "She'll pay for what she's done."

In the months before she died, Lane stalked Miss Grice, the trial heard.

He put a tracker device on her car and received notifications via a phone app every time it moved.

Lane initially claimed he bought the device to cut his insurance premiums but later admitted he fitted it underneath her car using a cable tie.

Prosecutor Philip Bennetts QC said Lane became "obsessed" with Miss Grice after forming a relationship with her in 2015 while they both worked at Brighton Fire Alarms.

He told jurors: "During their relationship, he stalked her. He put a tracker on her car and followed her movements.

"That obsession with her translated into killing her. He would not allow anyone else to be with her."

Miss Grice complained about her tyres repeatedly being let down, of receiving heavy breathing phone calls from withheld numbers and of Lane following her.

Lane also targeted Mr Cooke by placing a note on his car which read: "Dear Ash, Shana has and always will cheat on you. Happy New Year."

She was found dead face down on her bed in the smoke-filled room by Mr Cooke's father, Ian Cooke, after colleagues reported she had failed to arrive at work.

Lane dismantled the smoke alarm in the hallway and disposed of broken pieces of it under her bed in Chrisdory Road in the Mile Oak area of Brighton.

Following the killing, mechanic Lane withdrew £60 from Miss Grice's bank account and later went to a McColl's store to check a lottery ticket.

He then went to work at SE Tyres in Burgess Hill, where he was arrested.

As he was held, he simply said "Murder" and made no further comment.

Lane told a series of lies in interviews, including that he had not been to Miss Grice's home on the day of her murder. He later admitted he had to check why she had not gone to work.