When the police arrived at the Moana Ave house, they found Evelyn Kathleen Sen inside with superficial wounds to her wrists.
Her daughter Maggie Renee Watson was lying dead in the living room.
The little girl was cold and stiff - the officers knew she had been dead for some time.
Sen, who told paramedics there were demons in her house and that she was possessed by them, was taken away for treatment and police began to piece together what had happened in the modest duplex with the white picket fence in the sleepy Onehunga street.
Maggie Watson with her mother mother Evelyn Kathleen Sen. Photo / Supplied
Maggie's mother charged with murder
As she was transferred into the custody of mental health professionals, two autopsies were carried out to establish how Maggie died.
The first was inconclusive but the second confirmed that Maggie had not died naturally - rather she had died because of a massive drug overdose. The child had ingested a huge amount of mirtazapine, an antidepressant used to treat major depressive disorders.
Maggie had more than 130 times the adult dosage in her little body.
Sen, the only person in the house when Maggie died, was charged with murder.
A month before she was set to go on trial in the High Court at Auckland, Sen was found not guilty by reason of insanity.
The court ruled that when Sen murdered her only child she was suffering from a significant mental illness and psychiatric delusions.
She thought her child was possessed and that evil demons were torturing her.
Sen was unemployed and on a benefit but Maggie wanted for nothing and photographs of her last birthday party show a happy little girl, a sparkling crown on her head, smiling amid a pile of wrapped presents.
Maggie with her grandparents Clifford and Pat Sen. Photo / Supplied
She 'was not living in this world'
In March 2015, Sen took Maggie to Malaysia for a two month holiday. It was then that the cracks started to show and Sen's parents started to worry.
It emerged at the insanity hearing that Clifford and Patricia felt Sen was "was not living in this world" and that "her mind goes to a different arena".
They revealed that while in Malaysia, Sen accused her father of sending her to New Zealand to be sacrificed c "possessed by unclean spirits". Her daughter was similarly afflicted, she claimed.
Clifford and Patricia Sen took their daughter to a traditional healer to "exorcise" her.
The healer believed Sen was "deeply troubled" and noted she had "psychotic symptoms", that there was evidence of paranoia and depression.
But no one thought Maggie was, at any stage, in danger.
Sen and Maggie returned to Auckland in mid-June and less than two months later the child was dead.
Friends of 4-year-old Maggie Watson gathered outside her home on Moana Ave, Onehunga, where she was found dead on August 7. Photo / Greg Bowker
'Demonic and evil spirits'
The killer mother never spoke to police about what she did to Maggie, but she opened up to forensic psychiatrist Dr Mhairi Duff.
Maggie had been waking up in the night "screaming", Sen told Duff.
Night after night it happened, and Sen was convinced this was evidence of Maggie being tortured by demonic and evil spirits who wanted to possess her.
Sen could not bear to see her only child suffer and thought many times about killing her, and then taking her own life. For a long time she was able to resist.
But on August 6 it all became too much and Sen, driven by a desire to "save and protect" Maggie from these demons, to save her soul, took the action she thought was right.
"It came to her very suddenly in clarity," Duff said.
It is unclear how she got Maggie to take the tablets, Sen maintained her right to silence and never spoke to police, but it is thought the child ingested them that afternoon.
"I must have been demonically possessed. The devil got inside my head. It was wrong," Sen told Duff.
Duff said despite having "untreated psychiatric delusions" she had managed to function as a mother and cared well for Maggie until her death.
"There was no indication that the child had been neglected or abused," Duff said.
"There was no indication that the act on the day was anything other than an attempt by a good mother to protect her child from an unacceptable fate that no one else was able to help her escape," she said.
"She believed this act was morally right. She had a clear intention to kill herself as well as her daughter. She continues to ask herself why she lived and her daughter died."
