It's a gripping whodunnit on one level; on another, a clever character study. Shaw had been reading Trust: A True Story Of Women And Gangs by Pip Desmond and was thinking about people visiting family members in jail when the character of Jessica, a woman still grappling with her demons, came to her. As the chaos mounts, and a second body appears, Jessica even starts to doubt herself - could she have blacked out and done something terrible?
"She's been bad, off the rails, and she doesn't know how to deal with it," Shaw explains.
The rest of Shaw's research sounds rather idyllic. Fly-fishing expeditions on the Tongariro river, trips to the National Trout Centre. At the time, Shaw and her partner lived in Auckland and would make the drive down for the occasional leisurely weekend. She always knew Turangi would make the perfect location for a story.
"It seemed to me there are two Turangis, one on either side of the highway. You've got the beautiful area, full of gorgeous lodges and homes, but the other side of town is quite different. It has a different demographic. That disparity interested me as a novelist."
Two drafts in, she and her partner moved to Taupo, a move she says was completely unrelated to the shadowy world of her characters. But moving nearby meant she felt a little concern over what the locals might think about the book. Its page-turning suspense elevates it from becoming too grim, yet the novel explores dark subject matter: murder, drug use, sexual abuse.
"I tried to make it as true as possible to the township but, because I don't live there, I was taking a lot of licence, especially because it's quite dark. I believe if you're telling a good story about characters, that's what matters, rather than the bloody murder or the horrible crime. Also when something like that happens, it's interesting to show how people react and what leads up to it. It's part of the puzzle with a crime novel. So you're not just writing about gratuitous violence."
Shaw finds a comfortable balance between leaving things to the imagination yet telling the story in a visual way. So much so that it's easy to imagine it on television. Not surprisingly, when she saw Jane Campion's Top Of The Lake, she found its eerie, small-town murder mystery enthralling. The Children's Pond strikes a similar, black-humoured, bleak tone. Shaw's style is taut, her sentences often clipped, the dialogue terse, a style she admires in Australian crime writer, Peter Temple.
"My style is almost abrupt," she says.
Shaw has written a hugely diverse body of work and has held the Buddle Findlay Sargeson Fellowship and the Creative New Zealand Berlin Writers' Residency; in 2005, she was Writer in Residence at the University of Waikato. But that didn't make it any easier to get The Children's Pond published.
Shaw had set up her own imprint, Pointer Press, before she finished this novel, to publish other books. (She also mentors creative writing students through correspondence school and advises on manuscripts.) After a year of sending her own manuscript to publishers in New Zealand and Australia, and getting "really good, considered responses" yet no offers, she got frustrated and published it herself.
"The publishing world, especially in New Zealand, is risk-averse - they don't want to publish books that won't sell heaps of copies so they go for safe options or well-known authors. I still can't understand it, in all modesty. It's a really hard culture now, and a lot of really good published authors are not being published any more."
She has also written several short stories, children's books and young adult fiction, and several novels for adults, covering broad subject matter: an inter-racial love story in Hitler's Germany in The Black Madonna (2005), three sisters confronting the past in City Of Reeds (2000), early circus life in Dreams Of America (1997). If there's a common thread, it's her ability to create an unsettling atmosphere, and the fact she often sets her stories in provincial New Zealand.
"Maybe it's because I grew up in the Waikato, I'm not sure. Another thing is I've always been drawn to writing about violent crime."
She is also fond of revisiting her characters' pasts, through flashbacks, which help to add more complexity to the characters, she says. Plot is at the heart of this novel, but Shaw says she didn't sit down and plot it bit by bit; rather she let it unravel. The more she writes, the more ideas came.
"I'm interested to know what happens because of these incidents, and how that affects the community. It is ripples in a pond. Also it's about people's motivations. I love to know why people do things and I think that's part of why I write."
The Children's Pond (Pointer Press $29.99) is out now. Tina Shaw will appear at the Going West Books and Writers Festival in Titirangi, September 12-14.