The centrepiece of the movie The Men Who Stare At Goats is a US Army experiment in which a soldier kills a goat simply by staring at it. This is fiction, but based on a supposed real-life test reported in Jon Ronson’s non-fiction book of the same name. A martial arts master called Guy Savelli claims to have carried out the killing.

Scientists have been looking into magical murders for some time. In a 1942 paper on “Voodoo Death”, anthropologist Walter Cannon compiled histories of cases witnessed by trained doctors. These were typic­ally caused by “bone-pointing” in which a shaman or witch points at the victim and curses them, telling them they will die.