A 'fear detector' that has been developed by scientists from City University London can apparently sniff out human fear.
The device depends upon recognising a pheromone - or scent signal - produced in sweat of a scared person.
The researchers hope that the novel equipment would make it possible to identify individuals at checkpoints who are up to no good. Terrorists with murder in mind, drug smugglers, or criminals on the run are likely to be very fearful of being discovered. However, calm they might appear on the surface, their bodies could give them away.
"The challenge lies in the characterisation and identification of the specific chemical that gives away the signature of human fear, especially the fear in relation to criminal acts," the Telegraph quoted Professor Tong Tun, the team leader, as telling The Engineer magazine.
Although the research is at an early stage, the researchers' aim is to develop a prototype device in the next two to three years.
They will look at the obstacles to reliable detection such as the effects of perfume, and natural differences between individuals.
US scientists had earlier provided evidence that smell of fear is real. They had studied the underarm secretions of 20 terrified novice skydivers.
The researchers also found that people appear to respond unconsciously to the sweat smell of a frightened person. During the study, researchers put absorbent pads under the armpits to soak up sweat from the skydivers.
The other volunteers were not told the true nature of the experiment, and asked them to sniff the samples through a nebuliser.
The brain scans showed that the scent of sweat from the scared skydivers triggered a heightened response in brain regions associated with fear.