“The ITS is a movement that, in accordance with its ideals, opposes any development of neo- or nanotechnology anywhere in the world, and they are linked to attacks in several different countries of Europe, including Spain and France,” Castillo said.

He confirmed that the package had been disguised with labels from a well-known express package service, but did not say which one.

A manifesto signed by the group and posted on a radical website said that it has no remorse, and that its goal—having the guards deliver the package to the intended professor—was accomplished.

Nanotechnology, or the study of manipulating matter on an atomic and molecular scale, may be able to create many new materials and devices with a vast range of applications, such as in medicine, electronics, biomaterials, and energy production.

However, nanotechnology also raises many of the same issues as any new technology, including concerns about the toxicity and environmental impact of nano-materials.

The manifesto expressed fears that nano-particles could reproduce uncontrollably and form a “gray goo” that would snuff out life on Earth.