Peter John Enright's parents, Maureen and Michael Enright, didn't report him missing when he disappeared in 1968 or 1969 aged three or four years old.

But police allege his mother, now 76, murdered him at their Brisbane home and may have had a hand in burying him in the yard.

Detectives took her into custody earlier in October and charged her with murder after interviewing the surviving family.

Bone experts and forensic officers then started searching for Peter's remains at the family's Inala home, where they had lived since 1966.

They've removed decades of debris from under the house and used ground-penetrating radar to scan beneath the earth.

But on Friday, police announced no skeletal remains had been found during the eight day search.

Peter was born June 17, 1965. His father Michael died in 2018.

Enright appeared in Richmond Magistrates Court on October 22

Her case will be re-mentioned on December 11.

Australian Associated Press