Miss Bernal was shot in the back of the head
The killing of an employee at a Harvey Nichols store by her ex-boyfriend "could not have been reasonably foreseen", a coroner has ruled.
Westminster coroner Dr Paul Knapman said Clare Bernal, 22, was unlawfully killed when she was shot dead by Michael Pech, who then killed himself.
She was shot in Knightsbridge, west London, in September 2005.
Giving his ruling on Thursday, Dr Knapman said the Met had made a number of mistakes in handling the case.
These included charging Pech with a less serious offence than the one recommended by prosecutors after he was first arrested, and failing to fill in relevant forms.
At a previous hearing, he had heard how a "low risk" assessment was given to Pech by police after Miss Bernal reported his behaviour.
Metropolitan Police (Met) Commander Steve Allen, head of the Violent Crime Directorate, had admitted that a crucial risk assessment form had not been completed but said this had not made "one iota" of difference to the eventual outcome.
The coroner insisted these shortcomings were "not serious" and instead criticised a culture of blame between the CPS and the police in the case.
He said: "Forget about human fallibility, or even expecting people to do the impossible.
"In this case we do not need a scapegoat. We do not need a parcel of retribution to be passed to end in some person's lap."
He concluded: "I am satisfied this outcome could not have been reasonably foreseen bearing in mind the resources available."
Dr Knapman said he would write to the Met and ask the force to consider cutting down on paperwork so officers could be freed to spend more time on operational duties.
Pech shot Miss Bernal in front of shoppers at Harvey Nichols
The coroner singled out for praise the inexperienced Pc Bibi Shah who was assigned to Ms Bernal's case. He said she had carried out her duties "in the best tradition of the old spirit of the Met".
Slovakian Pech had taken cocaine before walking into Harvey Nichols on 13 September.
The inquest was told he crept up behind Ms Bernal and shot her in the back of the head.
Then, as she lay on the floor the 30-year-old former security guard at the store fired three more bullets at her.
The former soldier had begun stalking Ms Bernal, from Dulwich, south London, following the end of their brief relationship in 2005.
He was arrested and charged with harassment, but while on bail managed to travel to Slovakia and smuggle back a pistol.
He shot Ms Bernal, who is originally from Tunbridge Wells in Kent, eight days before he was due to be sentenced after pleading guilty to the harassment offence.
At an earlier inquest, Dr Knapman recorded a verdict of suicide for the death of Pech.
Patricia Bernal is campaigning for stalking law reforms
Ms Bernal's mother Patricia, of Groombridge, East Sussex, said: "There doesn't seem to be anything in place once somebody is let out on bail to actually look to see what the perpetrator is up to.
"It didn't occur to anybody that perhaps he (Pech) would carry out his threat. He said to Clare quite clearly, if you report me I will kill you."
Since Ms Bernal's death her mother has been campaigning for stalking law reforms.