The heartbroken family - which has posted musical tributes to the girl online and is reeling after the death - is now under a full-scale police probe.
Police this week confirmed to the Herald on Sunday that their investigations into the death had been upgraded to a homicide.
Stevve Ella Lawson was only two weeks past her first birthday when she was flown by rescue helicopter to Starship hospital on April 29 in a critical condition with head injuries.
Stevve - called Stevie by her family - died on May 2. Detective Inspector Kevin Hooper, of Waitemata police, said Stevve had been living with her mother Ajhalia Trotter, and her partner, Todd King, near Wellsford, North Auckland.
Trotter recently removed a Facebook status that said she was in a relationship with King.
On April 30 Trotter asked her friends to "pray for Stevie".
"She started having seizures on Tuesday night and was choppered to Starship.
"She is in the best care possible in the intensive care unit here. Stevie is going for an MRI now. We need everyone's prayers.
"She's a very sick little girl right now."
Trotter's father, Perry, declined to comment but criminal lawyer Eb Leary phoned the Herald on Sunday on his behalf.
"Whatever has happened is not the fault of Ajhalia Trotter. I can tell you that fairly and squarely," Leary said.
Leary said Trotter shared custody of the toddler with former partner Steve Lawson and Stevve had been in his care.
Stevve's death certificate shows her mother was "never in a legal relationship" with Lawson.
"We don't know what happened to this child but he had custody when the injury, if there be any, occurred," Leary said.
The veteran lawyer also claimed police had misinformed him about the investigation, but would not elaborate.
"They've been economical with the truth to date which is disgraceful," he said.
A service was held on May 7 for Stevve at her grandparents' home.
Ajhalia's sister Avya Trotter, a young singer-songwriter who has performed with Jamie McDell, posted a musical tribute on YouTube called Stevie's Song.
"A few weeks ago, on May 2nd, my sister's beautiful daughter passed away very suddenly. Stevie Ella had just had her first birthday.
"I started writing this song about her a couple of months ago. I could hear her laughing in the next room as I was writing it.
"Never did I imagine this would happen. The day after Stevie passed away I completed this song.
"Stevie was our sunshine. She was just so happy all the time. We miss her so much."
Police were already busy with the Blessie Gotingco murder inquiry on Auckland's North Shore.
Detective Inspector Hooper, said: "Investigations are ongoing to determine how Stevve's injuries were caused and no further comment is expected to be made at this time."
