Paranormal investigators say they still do not know whether or not ghosts are residing in Plymouth's naval docks.
Many of the prisoners executed at the docks were French
A team from the Paranormal Research Organisation (PRO) and psychic investigators are expected to talk about their experiences next month.
The PRO spent two nights investigating the Hangman's Cell which the Royal Navy wants to turn into a tourist centre.
The psychics said they were convinced the cell was haunted, but the PRO said "evidence is minimal".
"Personally we found nothing scientific or otherwise to conclusively make such a claim," said Ian Addicoat of the Cornwall-based PRO.
The seven-strong PRO team took along still and video cameras, tape recorders, laser thermometers, digital voice recorders and motion detectors, dowsing rods and meters for picking up electro-magnetic activity.
They did record some eerie noises, especially when they started humming the French national anthem and talking in French.
The Hangman's Cell was once home for 141 French prisoners-of-war who were later executed.
They also photographed some eerie-looking "orbs" - round balls of light which float mysteriously in the air and are thought to be a form of ghostly energy.
But the evidence did not point to anything extraordinary, said Mr Addicoat.
"We thoroughly enjoyed our two nights at the base and we all felt perfectly comfortable," he said.
"In answer to the question: Is the base haunted? Our answer would have to certainly be 'the jury is still out'."
The navy is planning to invite the investigators back to the base next month for a chance to air their results at a public meeting.
In the meantime, it is still exploring ways of getting funding for the visitor centre.