Police have included cadaver dogs in their search for Bernadette Walker, almost two weeks after declaring a no-body murder investigation for the 17-year-old.
Their investigation continued throughout this week in Cowbit, where they searched alongside the River Welland after an Underwater Search Unit attended last week.
Officers have been out daily to look for Bernadette, having searched garages in Walton and the fields and surrounding areas in Cowbit.
At the time of launching the no-body murder investigation, DCI Jerry Waite said: "Due to the length of time Bernadette has been missing and concerns she may have come to some harm, we made the decision to declare this a murder investigation yesterday morning.
"Whilst we hope we do find Bernadette alive and well, there is every possibility this may not be the case therefore my team and I will do everything possible to find out what has happened to her and bring any offenders to justice."
Bernadette's parents Sarah and Scott Walker, both of Century Square in Millfield, Peterborough, appeared at Peterborough Crown Court on September 16, charged with the murder of 17-year-old. They are expected to submit their plea on November 30, in preparation for a trial expected to take place on March 9.
Anyone with information should contact police either by using the online webchat function, or by calling 101 and quoting Operation Penshaw.