A mother who starved her three-month-old daughter then allowed the body to decompose inside a cooler bag in a shed has pleaded guilty to manslaughter mid-way through her murder trial.

Tamara Louise Thompson, 38, had been on trial accused of failing to provide proper nourishment to baby Destiny, whose 'extensively decomposed' body was discovered wearing a nappy and wrapped in a muslin cloth inside a cooler bag in July last year.

"Immeasurably sad."

That was how Supreme Court judge Stephen Hall described the death of three-month-old Destiny at the hands of her mother. 

After the child's body was found, instead of taking responsibility and feeling remorse, the mother consistently lied to police, health professionals and acquaintances about what had happened and denied being involved.

The trial was abandoned on Wednesday when Thompson pleaded guilty to the lesser charge of manslaughter.

Thompson, of Geraldton, was jailed for 10 years with a non-parole period of eight years after pleading guilty to manslaughter.

She could be released by July 2023, including time already served.

Thompson let her baby die "not because of any error but because of antipathy" towards her child, Justice Hall told the court.

Destiny was only discovered a couple of months after her death, her body decomposing inside a cooler bag in a shed.

Until then, Thompson, who had five other children, had lied to people including her daughters, saying the baby was in the care of the Department for Child Protection because she needed a rest.

Thomson's landlord alerted the department, who then involved the police, after she inspected the property and found it in a disgusting state and the whereabouts of the baby unknown.

Defence counsel Helen Prince told Justice Hall that Thompson's borderline personality disorder and depression had affected her judgment and should be mitigating factors that reduced her sentence, along with the fact she had pleaded guilty.

Prosecutor Carmel Barbagallo rejected that, saying Thompson had refused help from welfare agencies and freely made the choice to use the illegal drug methylamphetamine, which had more of an impact on her ability to function than depression.

Destiny was the result of a casual encounter with her drug dealer.

"There was a lack of genuine remorse," Ms Barbagallo said.

A police interview lasting four hours and 13 minutes had involved her saying "I don't know what happened", "I can't explain it" and "trying to blame someone else.

"These were well-thought out lies and were about self-preservation," Ms Barbagallo said.

It took several hours for her to admit the baby “might” be in the shed, where the infant’s body was found, partly mummified.
Prosecutor Carmel Barbagallo said during a sentencing hearing last week that Destiny had a fractured rib but her body was so extensively decomposed the official cause of death could not be ascertained.

After she was arrested, Thompson told police she was relieved when Destiny died, didn’t know what had happened to her body, and didn’t care.

Thompson had previously been convicted in country Victoria in 1998 after her one-year-old son was found with a fractured arm.

Thompson was also criticised by Justice Hall and received less of a discount for pleading guilty late in the process after her nine-year-old daughter became a witness. 

sources: Daily Mail / 9 News