Police are investigating "new lines of inquiry" after receiving phone calls about double killer Christopher Halliwell.
A senior detective says there are more victims' families who still haven't got justice because he believes the Swindon taxi driver may have killed others.
The 52 year-old was already serving a life-sentence for the murder of Sian O'Callaghan, 22, who he abducted in his taxi as she made her way home from a night out four years ago.
Detective Superintendent Sean Memory says he is now talking to police forces across the UK about unsolved crimes and missing people:
It seems very strange that there's an eight year gap between Becky an Sian's murders, and no offending apparently in between. I don't think that these are his only two offences.
Outside Bristol Crown Court, Becky's father told the media how the last few years had left him "mentally scarred" and "angry". He claimed we will never get the real truth:
In summarising the case, the judge spoke directly to Becky's family saying they've endured "every parent's nightmare" but hopes the verdict may bring some solace:
You have had to live with every parent's nightmare of a missing child and then the discovery that she had been dead for some years buried naked in a field. You have been deprived of the opportunity we all want to say farewell to our closest and dearest and then you have had to live through the criminal processes as Christopher Halliwell was brought eventually to justice.