Police missed a string of chances to stop a ritualistic killer before he murdered a mum in her own home.

Officers were repeatedly warned by the Italian authorities and local residents that Danilo Restivo was suspected of a previous killing. But they shut a line of inquiry into the monster a month before he attacked his neighbour

Heather's body was found in her bathroom by her son and daughter, then 14 and 11. Her throat was cut and she had been bludgeoned with a hammer. The seamstress had a clump of someone else's hair in her right hand and a lock of her own hair beneath her left hand.

Restivo, 51, has another 27 years to serve for Heather's murder before he becomes eligible for parole - . They want him to serve a separate 30-year term for the murder of Elisa Claps, 16, who disappeared in Potenza, southern Italy on 12 September 1993. Heather was murdered five months after South Korean student Jong-Ok Shin, known as Oki, was stabbed to death in the Dorset town. Like his other victims, Oki was stabbed to death on the 12th day of the month and a clump of hair was found close to her body. She was killed with the same type of knife later found on Restivo who was living three roads away from the murder scene.

Official records show that in the weeks after the murder, were contacted by three local residents warning them about the Italian. One described a conversation they had with the "creepy" murderer about Oki's death in which he allegedly said: "It must have been a big chef's knife to go right through her." 'Action 376' was set up by police stating that Restivo was suspected of a murder in Italy. An officer was allocated to investigate but the line of inquiry was given the lowest possible priority.

In August and September Portenza police sent two letters to Dorset Police via Interpol saying they were aware of Oki's murder and warned that Restivo was living nearby. They said that he was "gravely suspected of murder", was "psychologically unstable" and had sexually assaulted other girls. In October Restivo's landlady made a police statement saying he was a suspect in the murder of a girl in Italy. Nine days later the investigation was shut down without police having spoken to Restivo. He murdered Heather the following month.

Restivo was never made a suspect in Oki's murder. It was only after three trials that was finally convicted in 2005. Benguit continues to protest his innocence. Concerns have been raised about a key prosecution witness, a prostitute and heroin addict known as BB, who claimed that she had witnessed the murder. Five other witnesses have admitted they lied at the trial.

Benguit's lawyers have lodged a case with the Criminal Cases Review Commission. Restivo was found guilty in his absence of murdering Elisa after her body was finally discovered in March 2010 - nearly eight years after Restivo came to live in the UK. The then priest, the late Don Mimi Sabia, was a close friend of Restivo and he stopped a thorough search of the church where Elisa had been hidden. While under investigation for Heather's murder, Restivo was put under surveillance and on the 12th of one month, police were so concerned that they called in uniformed officers to search him. They found a fileting knife, two pairs of scissors, a balaclava and gloves. He was jailed for life for Heather's murder at Winchester Crown Court in 2011.

Dorset Police failed to answer a number of questions about safeguarding actions taken before Heather was killed. It said in a statement: "Our investigation into Oki’s murder was thorough, detailed and very complex. We submitted our evidence to the Crown Prosecution Service, which considered there to be sufficient evidence to charge Omar Benguit with Oki’s murder and proceeded with the prosecution. This case has been through a series of reviews and any matter surrounding concerns regarding this conviction is ultimately a matter for the CCRC and the Court of Appeal. Dorset Police would follow the direction and instigate investigations if directed by the courts and responsible authorities. As always, our thoughts are with Oki’s family and friends who remain devastated by their loss. Our thoughts are also very much with the family and loved ones of Heather Barnett for their devastating loss."