It follows the aftermath as Carla struggles to come to terms with what's happened and Ben faces the consequences in prison. Their stories continue to interweave after Carla requests a meeting through the restorative justice process.
"Very early on, I had two voices in my head: Carla and Ben's. I wanted to bear witness to the wider story, but the more questions I asked, the more elusive answers seemed to be," Sussman says.
The mother-of-two, who lives in rural Auckland, spent two years researching the novel, immersing herself in the world her characters inhabit. She met staff and inmates of the prisons featured in the book: Mt Eden, Paremoremo and the Northern Correctional Facility's Ngawha unit, a marae-style unit aimed at rehabilitating young Maori offenders by reconnecting them with their culture.
Having emigrated from South Africa 27 years ago, Sussman felt "a huge onus of responsibility" to present the character of Ben authentically.
"His world was largely foreign to me. I really didn't want to come across as a cliched white middle class female writer."
The 51-year-old qualified as a GP after she moved to New Zealand in 1989. She says as a GP, you're in a somewhat privileged position because people dispense with a lot of artifice when they're unwell. "You see people at their most raw and vulnerable and that gives one great insight to the human condition."
Sussman took a year out from her medical practice to write when her children were young and her husband was working long hours as a surgeon. She says it fulfilled a need to be creative which was growing within her.
Her first novel, Shifting Colours, explored cultural identity through the story of a black girl adopted by a white couple who leave South Africa. The Last Time We Spoke took her in a new direction, writing Maori characters. Sussman believes Pakeha authors can write Maori characters as long they write with respect and integrity, and do sufficient research to honour the character.
She made a major change in her final drafts, adding the voice of a Maori ancestor. Despite the pressure to publish at that point, she says something didn't feel right. "I realised I had a very clear idea of why Ben's family were the way they were, but I needed to place them on a wider stage in the context of time and history. A Maori colleague who read the final draft recently thanked me for 'channelling our tipuna and atua so well'. I was very grateful for her validation."
Sussman was also anxious to climb beneath stereotypes and says one reason she opened with the crime was because she wanted readers to make the initial knee-jerk responses and then to unravel them.
Fortunately Sussman's portrayal of Ben is neither idealised nor sentimental and she offers no simple solutions. She says it was crucial to give both characters equal weight and she didn't want Ben's story to overshadow the terrible anguish and pain Carla suffers.
Although the book opens with violence, she chose not to make the details too explicit saying she wanted to avoid gratuitous violence because it's very easy to become inured: "Often the unsaid has more power and impact."
She also avoided a "cliched happy ending" but does believe it's the author's responsibility to always offer hope. "Even as a doctor, you may get results back that would suggest a patient has little hope but I don't think we can ever say there is no hope. "
In her spare time, Sussman helps manage the Auckland Regional Charity Hospital she set up with her husband eight years ago. It provides free surgery for people falling through the cracks in the health system because they can't get on a waiting list and can't afford to go privately.
Four private clinics on the North Shore provide free theatre time to volunteer doctors who perform surgery on people with conditions affecting their quality of life; many are able to re-enter the workforce as a result.
Now her children have grown, Sussman is looking for something else to complement her often insular writing work. Inspired by the Howard League, she'd like to teach English to prisoners.
"One day at Ngawha I saw a 50-year-old man getting help to fill out an application form because he couldn't read. I was struck by that. Getting to 50 and not being able to engage with the world with the currency we all use must be an incredible disadvantage. We can't just lock people away for years, then let them out and hope they're not going to do the same thing again.
"Unless we throw away the key we need to give people the tools to succeed next time around, and literacy is a very small example of that."
THE LAST TIME WE SPOKE
(Allison Busby, $33)
