Two teenage girls from Midhurst and one from Guildford have pleaded guilty to attacking a 14-year-old girl with a crowbar.
Bognor: Stabbed Young Mum 'Let Down' By Agencies
An inquest jury has criticised police and the CPS for failing to safeguard the life of Cassandra Hasanovic.
The 24-year-old's mother has now called for a public inquiry after she was stabbed to death by her estranged husband in front of their young children in West Sussex.
Sharon De Souza said her daughter had been let down by Sussex and Kent police forces and the CPS and that "a number of serious failings'' had led to her death.
A jury sitting in Chichester, West Sussex, returned a verdict of unlawful killing and criticised Sussex Police and the CPS for failing to take the appropriate steps to safeguard the 24-year-old's life.
The jury concluded that Sussex Police had failed to ensure Mrs Hasanovic's safety and said that they should have escorted her to a women's refuge on the day she was murdered.
The also found that Kent Police failed to arrest Hajrudin Hasanovic for breaching his bail conditions and that the CPS did not take a number of steps to safeguard Mrs Hasanovic's life, including failing to apply for her estranged husband's bail to be withdrawn and failing to inform her of the special measures that might have been available to help her give evidence against him in court.
Mrs Hasanovic was about to be driven to a women's refuge when he appeared at the side of her car and plunging a knife into hie wife outside her mother's home in Bognor on July 29 2008.
Hasanovic, who was known as Harry, was facing deportation at the time of the killing and feared losing a custody battle for the children. He was jailed for life, with a minimum of 18 years, for her murder at Lewes Crown Court on May 1 2009.
Following the verdict, Mrs De Souza said: "My daughter Cassie was a beautiful, courageous young woman, who did everything within her power to protect herself and her children.
"Although her situation was in the hands of three different agencies, ultimately these agencies let her down.
West Sussex Coroner Penelope Schofield said she would be writing to the Association of Chief Police Officers (Acpo), Sussex Police and the CPS to recommend that information on domestic violence cases be shared across forces.
She also said there should be better policing in respect of non-molestation orders, a central point of contact where breaches could be reported and that training to deal with domestic violence cases should be addressed.
Sussex Police said as a direct result of Mrs Hasanovic's murder the force had reviewed its risk assessment procedure for officers responding to allegations of domestic abuse.
Detective Chief Inspector Pierre Serra, from Sussex Police, said: "We continue to express our sincere condolences to Cassie's family who have suffered this tragic loss of a mother and daughter.
"Sussex Police acknowledges the verdict of the jury in this case and awaits the Coroner's letter highlighting points raised in the inquest.
"This case was a watershed moment for Sussex Police and we have already learnt a number of important lessons from it in terms of how we deal with cases of domestic abuse.
Jaswant Narwal, Chief Crown Prosecutor for the CPS South East, said: "Our involvement with Cassandra dates back to a complaint of domestic violence sexual assault that she made to the police in 2007.
"For a number of reasons, a prosecution was not brought. It is now clear that there were shortcomings in the way in which we dealt with Cassandra's case."
She said a Rape and Serious Sexual Offences (RASSO) Unit staffed by specially trained lawyers was established in the South East in 2011.
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