A Harvey Nichols beauty consultant has described how she saw a man point a gun at her colleague's head.
Pech would watch Ms Bernal through mirrors at work
Victoria Daniels told Westminster Coroner's Court she heard five shots as Michal Pech shot ex-girlfriend Clare Bernal, then turned the gun on himself.
A verdict of suicide was recorded for Pech, who was due to be sentenced for harassing Ms Bernal, 22.
The coroner adjourned the inquest so evidence can be gathered to see if the judicial system failed Ms Bernal.
The court heard when Ms Bernal ended their relationship, security guard Pech began following her, telling her he loved her, then positioning himself in the store so he could see her in a mirror.
Guilty of harassment
Pech, who had threatened to kill Ms Bernal in March, had been on bail on condition he did not contact her or go to Dulwich Village, south-east London, where she lived.
He had been due to be sentenced on 21 September after pleading guilty to harassment. Ms Bernal, originally from Tunbridge Wells, Kent, was killed on 14 September.
Joshua Dubin, representing Ms Bernal, applied for scope of the inquest to be broadened so the coroner could look into alleged failings in the law enforcement systems, rather than just establishing how she died.
Mr Dubin said: "There is arguably a system failure here that has led to the death of this deceased and it gives rise to concerns about deaths or potential future deaths of others."
But a row broke out in the coroner's court between Ms Bernal's divorced parents - her father accused his ex-wife of not taking the complaints about Pech seriously.
Mrs Bernal wept as she said she had believed police were in control of the situation adding: "That is my mistake, and I have to live with that."
Earlier, Miss Daniels told the court said she saw Pech, who had taken cocaine, sliding around the beauty counter where Ms Bernal worked.
"I thought he might have been a boyfriend surprising her or a stupid customer who wanted to ask her a question," she said.
"At that point, Clare was looking in my direction and I smiled at her because it was time to go home and then he pulled a gun out."
She told the hearing she grabbed a colleague and ran outside.
"There was one big bang and then I heard about three more - there must have been four or five shots."
Pathologist Dr Vesna Djurovic said Ms Bernal was shot four times - once in the back of the head and three times in the face.
Adjourning the case to 19 January, Dr Knapman said: "It may be that I will make a decision [on widening the scope of the inquest]."
In a statement after the hearing, Ms Bernal's mother Patricia said: "I was very close to my daughter and miss her terribly.
"I, like Clare, put my faith in the criminal justice system. I sincerely hope that a wider inquiry will help prevent this from happening to another woman."