She had once been a happy child, adored by her cousins.

Her aunty, Sheryl Mitsch, teared up as she recalled the little girl while giving evidence in the Supreme Court on Wednesday.

Charlotte died just three days shy of her first birthday in December 2004.

The prosecution had alleged she was attacked by her mother's boyfriend, Brett Penrose, 44, on that night after the baby had been left in his care.

The third day of the manslaughter trial in Melbourne focused on Charlotte’s health and her mother’s partying on the night.

But the drug use of her father was also under the spotlight.

Graeme Keen, who had not given evidence in any previous court or inquest hearings, was expected in the Supreme Court witness box as early as Thursday.

Charlotte’s paternal grandparents, Bob and Lesley Keen, were in court as was support for Penrose.

Mrs Mitsch told investigating police, after Charlotte's death, she believed the baby’s personality had changed when she visited after her brother separated from Renee Jones.

The woman had quickly partnered with Penrose.

“(Charlotte) sat wide-eyed and appeared stunned,” Mrs Mitsch said.

But she never saw bruising on the baby.

The two women had been close and bonded over Ms Jones’ first child.

That changed after the separation.

Charlotte spent five days at Royal Children's Hospital before her life support was switched off.

Mrs Mitsch said she was concerned at the hospital when Ms Jones spent more time buying her daughter presents, than by her side.

“This incident will stick with you forever,” she said.

The knowledge Mr Keen had been taking drugs around the time of Charlotte’s death did not stop Mrs Mitsch describing him as “the perfect father”.

She said she was not aware of specifics of her brother’s drug use.

The Riverview Child Care Centre director in 2004, Kathryn Cohalan, told the jury Charlotte was a normal baby with no signs of abuse during her seven months at the centre.

“I cannot recall her coming in from home with anything (bruises) at all,” she said.

“If it was something we suspected to be more sinister, we would have to notify the department (of human services).”

Ms Cohalan said Charlotte had been “quite attentive” and Ms Jones kept her daughter clean and well presented, but lacked in sharing details about the baby’s needs with staff.

The trial in Melbourne, before Justice Terry Forrest, continued Thursday and was expected to run until mid next week.