The mother of murdered Becky Godden-Edwards has vowed to fight for justice for her daughter.
Karen Godden-Edwards is campaigning to have her daughter's case reopened.
Christopher Halliwell led police to her daughter's body which was buried in a field in Eastleach, Gloucestershire, in 2011, and even admitted killing her.
But the taxi driver, who was jailed for 25 years after being convicted of the murder of Sian O'Callaghan, was never prosecuted for the murder of Godden-Edwards.
A senior officer's failure to follow the rules by cautioning Halliwell meant the murder charge had to be dropped.
The campaign launched by Karen Godden-Edwards, dubbed Justice for Becky, calls for a change in the law which currently means information given by suspects before or without them having been properly cautioned is inadmissible in court.
