He said that an x-ray conducted later "revealed the presence of a metallic object with wires attached to it".

BBC: India

Previous studies of Trois Hommes Armes de Lances had used X-ray fluorescence - which yields a list of all the atoms within an object - but showed that there were atoms present in the work that were not present on the surface.

BBC: Terahertz scanner reveals hidden fresco at Louvre