THE parents of missing teenager Russell Bohling admit they will probably never know what happened to their son after a new search of a former RAF bunker revealed nothing.
Dad Roger Bohling had raised concerns over the extent of the bunker search shortly after Russell, 18, went missing.
However, fire crews carried out a training exercise at the bunker on Wednesday and no body or any further clues as to Russell's disappearance were found.
Despite a long fight over the way the case was handled and calls for a more rigorous investigation over possible third-party involvement, Mr Bohling admits it is time to try to move on.
He said: "I feel we will just have to live with this mystery.
"We are starting to clutch at straws and I don't think there's any more that can be done.
"We have to try to come to terms with the fact we will not get an answer. That is very difficult to cope with.
"We have to let go and maybe something will turn up in the future."
Russell searched for information on RAF Bempton, which was used by a witches' coven in the 1970s, shortly before his disappearance.
Mr Bohling says fire officers told him the brief for searching the bunker in March 2010 was to find a living person.
He met fire officers last summer, who said only heat-sensitive cameras and torches were used, which would be ineffective in the search for a body, while flooded areas were not pumped out and searched.
Mr Bohling praised the fire service for its efforts in carrying out the training exercise.
He said: "We are enormously grateful to the officers and men who took part in this meticulous search to resolve, beyond doubt, whether Russell's remains rested within the bunker or not.
"The fire service invited us along and we sat with the operations manager.
"We were able to follow the progress during the exercise, which lasted about three hours.
"There were seven firefighters, who went from room to room. We now know for certain he didn't suffer an asthma attack down there and collapse.
"We had to pay the farmer £1,200 to open the bunker up but he has been very co-operative and we appreciate that.
Russell disappeared on March 2, 2010, after he left the family home in West Ella for Bishop Burton College.
His Renault Clio was found at Bempton Cliffs the next day.
At the height of the investigation, there was a core team of 12 officers searching for Russell, headed by a detective inspector.
Sea, mountain and helicopter searches failed to locate Russell.
The family believe Russell was murdered but the police have always treated it as a missing person case.
The third-year anniversary of his disappearance is tomorrow.
• Training exercise helps give Bohling family closure
