James Mitchell - who runs the Scotland’s Secret Bunker museum in north east Fife - was alleged to have sexually assaulted two young women, one aged just 15, in separate attacks four years apart in sleeping accommodation at the underground bunker.
Mitchell, of Lower Largo, denied the charges against him at Dundee Sheriff Court and stood trial over five days.
Today a jury found Mitchell guilty on the charge of assaulting the girl that he later claimed had been touched by a ghost.
But because the jury found the second charge not proven - and the case relied on both offences being proven beyond a reasonable doubt for a conviction on either - a sheriff was forced to acquit him of all the charges.
One of his alleged victims told the jury that a man fitting Mitchell’s description had entered the bedroom where she was sleeping at around 4am, put his hand under the covers and touched her leg before sneaking out of the room.
She got up and, with a friend, left the bunker in the dead of night.
The second girl told how she was 15 at the time of the incident and that Mitchell had tried to kiss her before placing his hands on her private parts.
She said she told him no before he went on to carry out a sex act on her.
The court heard from Sergeant Kevin Petrie (36) who interviewed Mitchell over the first alleged attack, said to have taken place in August or September 2011.
Mitchell was asked if he had carried out the assault - which he denied, claiming he had only heard about the alleged attack from a relative.
Sergeant Petrie asked him: “What were you told or what do you think happened?”
Mitchell replied: “It was that long ago but somebody touched her leg.
“It was supposed to be a ghost because my daughter has seen ghosts in the place.
“We have had seances and lots of spiritual people in, spiritual people come down all the time.
“There was supposed to be ghosts.
“That’s what I’d heard.
“A ghost had touched her leg.”
The officer then put it to Mitchell that the alleged victim had felt her leg being touched, woken up, saw him then watched him leave the room.
He replied: “Piddle. Absolute rubbish.
“That is an absolute outright lie.”
Mitchell later added that the bunker was “pitch black” and so dark the victim couldn’t have seen what she told police she had seen.
Summing up the Crown case, fiscal depute John Adams told the jury: “There is enough evidence to find James Mitchell guilty.
“Why would the girls lie about this?
“What is the logical conclusion?
“I suggest that its that he is guilty.”
But solicitor advocate James McAteer, defending, said: “There is no corroboration between the charges and you can’t convict without both the charges.
“The Crown infer the bunker was a device to sexually abuse.
“There is no evidence that this is the case.”
Mitchell (58) denied one charge of sexual assault and three under the Sexual Offences (Scotland) Act 2009.
A jury of eight men and seven women took an hour and 20 minutes to find Mitchell guilty of the earlier assault but not proven on the subsequent attack.
Because the case proceeded under “mutual corroboration” laws a sheriff said it was “nonsensical in law” for one charge to end in conviction and the other lead to acquittal.
As a result Sheriff Alastair Carmichael recorded a not guilty verdict on the charge the jury found Mitchell guilty of and told him he was free to leave the dock.
Mitchell made no comment as he left court.