A mother covered up the death of her baby son for more than a decade by hiding his body at a north London home.
Victoria Gayle, 32, pleaded guilty to preventing his lawful burial at Kingston Crown Court on Wednesday, the Met Police said.
Scotland Yard said little was known about the baby but that he was last seen in late 2004.
Officers then searched a property in Fryent Crescent in West Hendon where they discovered the remains of a small child.
The body had been placed in a box and wrapped up, the BBC reported.
Gayle, who was on bail, admitted preventing a lawful burial but denied perjury and perverting the course of justice. The allegations will lie on file.
A Met Police spokesman said: "A special post-mortem examination took place at Great Ormond Street Hospital and the cause of death could not be determined.
"Further tests were unable to establish exactly how the child died and inquiries continue to this day.
"The skeletal remains have not been confirmed as that of the child who disappeared in 2004 and although Gayle has pleaded to the offence of preventing a lawful and decent burial, detectives continue to investigate the disappearance of the baby boy, the identity of the remains and are working closely with a number of partner agencies."
Gayle will be sentenced at Kingston on February 3.
A 50-year-old woman and a 52-year-old man, who were both arrested on suspicion of preventing a lawful and decent burial, have been re-bailed pending further inquiries.
A 38-year old man, who was arrested on suspicion of preventing a lawful burial and perverting the course of justice, has also been re-bailed.
