The cousin of New Zealander Rowan Baxter - who murdered his three children and wife Hannah Clarke in a deliberately lit car fire - says he had a series of affairs and had a dangerous sense of possession and entitlement.
Sandra Taylor says Baxter, who took his own life after killing his family, had a degrading view of women that fuelled his rage.
"Not that I'm saying Rowan is a victim, but Rowan has been raised by a father and his father and his father — and it goes onwards — that women are two things: to be the house cleaner and to be a prostitute," Taylor told 9 News.
Taylor said that after Hannah Clarke suffered through years of sexual, emotional and financial abuse, she finally broke free from their relationship and was planning to start a new life.
Taylor told Australian media outlets she offered Clarke her home as a safe haven as they feared Baxter, a member of the Warriors rugby league team in 2005, would harm his estranged wife.
Clarke died after Baxter poured and ignited petrol on her and their children - Aaliyah, 6, Laianah, 4, and Trey, 3 - when he ambushed them during the morning school run in Brisbane last week.
Taylor believed Baxter was cheating on his wife and had several affairs during his first marriage.
"We were at a family barbecue and he was at the grill and I walked over to him and he was sending hundreds of texts to other women," she told Daily Mail Australia.
"I know Hannah believed she wasn't the only one."
Taylor - Baxter's first cousin on his mother's side - also revealed how Baxter's behaviour became increasingly threatening, including an assault and constant stalking.
"Rowan was a man with a dangerous sense of possession and entitlement over his wife and children, particularly in the last three months, that I was concerned for," she said.
"This was a man with a level of hatred and disrespect for their mother so great that he would make this choice - the most horrifying and despicable of choices."
Taylor also spoke to 9 News, saying Baxter had a long history of vile misogyny.
"Rowan believed that women are two things - to be a house cleaner and to be a prostitute," she said.
Taylor said she reached out to Clarke - they both work in the same building - when Baxter made a long Facebook post about their custody battle, saying that he was being hard done by.
She said Clarke soon formed a network of safe houses, including Taylor's home, that the mother could run to if Baxter threatened her.
But Baxter was one step ahead and hacked into Clarke's phone using dodgy attachments and soon turned on Taylor.
"I started getting very worried because all of a sudden I started seeing dog faeces all over my driveway, and two of my pot plants were destroyed," she said.
"I didn't know how to tell her to that he kept walking by the building we both worked in."
Taylor believes the murders could have been prevented if he was given help for his mental health.
"He thinks he's done the right thing because there's been no mentoring for him, no one to make him see this isn't okay," she said.
"It's just been fear, control, mental, sexual, and physical abuse."
If you're in danger now:
• Phone the police on 111 or ask neighbours of friends to ring for you.
• Run outside and head for where there are other people.
• Scream for help so that your neighbours can hear you.
• Take the children with you.
• Don't stop to get anything else.
• If you are being abused, remember it's not your fault. Violence is never okay
Where to go for help or more information:
• Women's Refuge: Free national crisis line operates 24/7 - 0800 refuge or 0800 733 843 www.womensrefuge.org.nz
• Shine, free national helpline 9am- 11pm every day - 0508 744 633 www.2shine.org.nz
• It's Not Ok: Information line 0800 456 450 www.areyouok.org.nz
• Shakti: Providing specialist cultural services for African, Asian and middle eastern women and their children. Crisis line 24/7 0800 742 584
• Ministry of Justice: www.justice.govt.nz/family-justice/domestic-violence
• National Network of Stopping Violence: www.nnsvs.org.nz
• White Ribbon: Aiming to eliminate men's violence towards women, focusing this year on sexual violence and the issue of consent. www.whiteribbon.org.nz
How to hide your visit
If you are reading this information on the Herald website and you're worried that someone using the same computer will find out what you've been looking at, you can follow the steps at the link here to hide your visit. Each of the websites above also have a section that outlines this process.