Police failures led to the death of a woman who was murdered by her partner five years after he killed another girlfriend, an inquest has found. 

Susan Nicholson, 52, was murdered by Robert Trigg in 2011 after he killed Caroline Devlin in 2006. Trigg killed both women at their homes in Worthing, West Sussex, but neither death was initially deemed suspicious by Sussex Police.

On Monday, a jury in Crawley concluded that Sussex Police did not take reasonable measures to avoid harm coming to Ms Nicholson, despite the fact that they knew or ought reasonably to have known there was a "real and immediate risk" to her life.

The verdict was the result of a fresh inquest into the death of Ms Nicholson, which her parents spent years campaigning for after a coroner originally recorded it as accidental. 

The decision was overturned by the High Court after Trigg was found guilty of killing the two women and a new inquest was ordered. 

Jurors also found there was a "realistic possibility" that Ms Nicholson’s death may have been prevented if Ms Devlin’s death had been declared and investigated as suspicious.

Peter and Elizabeth Skelton look on as the couple's solicitor reads out a statement following the inquest into the death of their daughter, Susan Nicholson

Credit: Michael Drummond/PA

Peter and Elizabeth Skelton, Ms Nicholson’s parents, said they were "ignored and spoken down to" when they raised concerns about the circumstances of their daughter’s death. 

"We were treated like a nuisance and it was implied that we were lying or obsessive," the couple said in a statement read outside the inquest by their solicitor. 

"Instead of enjoying our retirement years, we have suffered mental torture for over a decade fighting to get justice for Susan. The delay in the criminal case, and the resulting delay to these inquest proceedings, have had a deep and traumatic impact on us and Susan’s whole family."

The couple added: "We did not know then the history of awful violence perpetrated by Trigg against Susan and other women, or about the death of his previous partner Caroline Devlin. Sussex Police did know. It has been agony for us to learn about what Susan went through prior to her death and the extent of the failings to protect her from him."

Sussex Police issued a fresh apology to the family in the wake of the jury’s verdict for "the failings of the force".

Assistant Chief Constable Fiona Macpherson said: "Susan’s family and friends have waited a long time to hear all the facts surrounding her death and our thoughts remain with them, and with the family of Caroline, at this difficult time.

"As the coroner noted in her closing remarks, Sussex Police have made extensive changes and improvements in the way in which it responds to cases involving domestic abuse in the 10 years since Susan’s death.

"Learning from these two cases has been used as part of our work to comprehensively revise our policies during this period.

"We respect the findings of the jury, and we now need to pause to reflect on these before deciding on any further action."

The case was first referred to the Independent Office for Police Conduct (IOPC) in February 2018 but it was dismissed 10 months later. 

On Monday, an IOPC spokesman said: "Following the inquest, if any fresh evidence was heard or conduct matters for specific officers are identified by Sussex Police, we would expect the matter to be re-referred."