A baby found entombed in a block of concrete was unlawfully killed, a coroner recorded on Monday.
Police reconstructed the concrete block in 2003
The unidentified baby girl, thought to be aged between four and six months old, was beaten and may have been sexually abused, an inquest heard.
A hearing at Workington Magistrates' Court in Cumbria also heard how the baby was still alive when entombed.
Her tiny body lay undiscovered for at least 15 years until the block was opened in a garage in Barepot in 2002.
Detectives found a DNA link between the baby, named Lara by police, and Anne Chadwick who used to live with her ex-husband Philip only 100 yards from where the youngster's body was discovered.
The pair, of Droitwich Spa, Worcestershire, were arrested last year after tests revealed Mrs Chadwick could be the baby's mother or sister.
But the couple were released without charge after it was found Mrs Chadwick could not have given birth to the baby.
Suspicion quickly fell on Mrs Chadwick's parents Joe and Sheila Thwaites who have since died.
The hearing also heard how it was possible that the baby was Mrs Thwaites' and she had hidden the pregnancy.
A post-mortem examination showed the baby had suffered a fractured skull, bruising to the abdomen and may have also been sexually abused, although this was disputed by one forensic pathologist, the hearing heard.
Coroner John Taylor said: "The evidence heard raises more questions than have been answered here today.
"The first question is, is Lara the child of Sheila and Joe Thwaites and sister to Anne and Yvonne. If not who are the parents?
"We know she had been abused in other ways during her short life.
"Despite the fact I don't have a cause of death, I'm satisfied beyond reasonable doubt that Lara was killed unlawfully."
Speaking after the two-day hearing, Mrs Chadwick said: "To be accused of having had a baby you have not had and to have murdered that baby is a complete nightmare."