Maidstone crown court in Kent was told that the case had been reinvestigated in 1998 using a new DNA test, and Harry Pennells, a retired lorry driver from Ticehurst, East Sussex, had been linked to the body found in Bedgebury forest in Kent in 1979.
Despite repeated police appeals, her identity remains a mystery, although she was between 25 and 35, six weeks pregnant, and possibly from the north of England.
Opening the prosecution, David Fisher QC, said that when the body was found, the head and body injuries were so severe that identification was not possible.
Pennels had been questioned days after; he admitted picking up a female hitchhiker but claimed to have dropped her off, and was not charged. However, specks of blood found in 1979 in a sleeping bag in his lorry and in the cab were re-examine in 1998, and linked to the deceased. The case continues.