Two brothers whose mother and sister were killed in a domestic abuse attack by their father have written a book about their ordeal.
Luke and Ryan Hart's lives changed dramatically after mother Claire, 50, and 19-year-old sister Charlotte were shot dead by Lance Hart in a leisure centre car park in Spalding in July 2016.
Hart, 57, then turned the shotgun on himself.
The murders followed years of emotional abuse and control experienced at the hands of the perpetrator and took place days after Luke and Ryan moved their mum and sister into a new home.
Now the pair, who have become advocates for domestic abuse awareness, say the often silent problem - described as a "national health issue" - is something they have a responsibility to tell people about.
Luke, 28, told the Press Association: "The book was written to help us gain control of our perspectives. It also allowed us to gain control and meaning in our lives.
"In these murders, the narrative is often left behind by the man who's written a murder note, and then the victims have no choice and no voice and we've grown up with that."
An inquest in October 2016 heard a 12-page murder note was found stored on a USB stick in Hart's car.
Operation Lighthouse - which was also the name given to the police investigation into the deaths - follows the boys' childhoods as they reflect on past decisions made by their father.
They now understand these decisions, which included a number of house moves, were ways to "create more control and sever support networks".
The 235-page book, which contains a foreword by Labour leader Jeremy Corbyn, describes the days leading up to the event and the moments they found out about the attack.
Luke said: "We spent our entire lives trying to break our mum and sister away from our dad. We got to that point - we succeeded - and then he killed them.
"A big challenge for us at that point was that it genuinely felt that there was nothing here for us."
Ryan, 27, said the book shows how they are trying to "live for our mum and our sister", by expressing their values and "passion" as they rebuild their lives.
The Surrey-based brothers have dedicated part of the last two years to "giving a voice to victims", and say the book needs to be read by people "of all backgrounds".
Ryan added: "The lighthouse symbolises that we're trying to shine a light on domestic abuse.
"We're trying to offer guidance and support to those who are suffering it and show them the way and illuminate domestic abuse for everyone in society and communicate that we need to look out for these behaviours."
Some 1.2 million women experienced domestic abuse in the year ending March 2017, latest figures from the Office for National Statistics show.
The latest femicide census report, out last December, shows an average of two women per week were killed by men in England, Wales and Northern Ireland. Nine out of 10 were killed by men they knew.
Katie Ghose, chief executive of charity Women's Aid, contributed to the book's preface, writing: "Domestic abuse is often hidden behind closed doors and sidelined as a private matter.
"By writing Operation Lighthouse, Luke and Ryan Hart have shone a light on the reality of coercive control and how our ability to be able to recognise and respond to this form of domestic abuse is a matter of saving lives."
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