The young son of murder victim Jody Meyers was indoors "looking for his mama" while his father was outside burying her body under fresh concrete, the Adelaide District Court has heard.
Neil Archer strangled his partner with the cord from a hoodie at their Mannum home in August 2015.
The 20-year-old woman's body was found — one month after she had been reported missing — under the concrete slab of a garden shed on Mr Archer's mother's property.
Margaret Archer, 57, recently made an 11th hour confession that she had helped her son cover up the murder.
She bought cement and a wheelbarrow which Neil Archer used as part of his crime, the court was told, along with $10 of phone credit on the victim's mobile.
Members of the young mother's family received a text message which misled them into believing she had gone away after a relationship break-up.
Prosecutor Peter Longson said Ms Meyers' two-year-old son was inside Margaret Archer's house while his father was disposing of the body nearby.
"There was clearly a time Your Honour when Elijah... was [inside] while his mother was deceased in the backyard — not buried but simply somewhere on that property," he told the court.
"We can only imagine what must have been said to that child who was looking for his mama."
He said the boy had been in the car every time Margaret Archer went to buy cement or phone credit.
'Crocodile tears' shed for TV cameras
The court was told Margaret Archer cried "crocodile tears" as she pleaded on television for Jody Meyers to come home.
"She wasn't worried about anybody but her family, she wasn't worried about anybody but Neil and herself," Mr Longson told the hearing.
Judge Paul Muscat questioned why Margaret Archer had taken so long to confess and said her late guilty plea reflected her prospects of rehabilitation.
The woman's lawyer Robert Kane said he could not explain why the plea had come so late into the court process but his client "accepted responsibility" for her role.
"Albeit [the plea] was at the latest possible moment, that notwithstanding saved the family and friends of Jody Meyers the anguish and trauma of being subjected to the process of a trial," Mr Kane said.
No submissions were offered to suggest any remorse or contrition.
The maximum sentence for assisting an offender convicted of murder is 10 years in jail.
She will be sentenced early next month.
