French police believe a fire that destroyed a Monsanto research center in Rennes, France, on Oct. 28 was deliberately set. Investigators said they “strongly suspect it was a crime, as no electrical or other sources were found.”

The blaze is thought to have been ignited from multiple points at the site specialized in maize research, as the smell of gasoline was evident in several places. Police spokesman Jakob Witten called it an act of “unprecedented violence,” saying that Monsanto sites in Europe have so far been the victim of fires of criminal origin.”

In France and other European countries. Monsanto has come in for fierce criticism over its genetically modified crops. In September, France became one of 19 countries to announce it would take advantage of the EU Commission’s scheme to opt out of planting genetically manipulated crops.

Under public pressure, the French government has also announced plans to ban Roundup, Monsanto’s flagship herbicide. It is not clear, however, whether the ban will stand up over the long term, in view of the European Parliament’s rejection of the Commission’s plans to let member states’ opt-out of commercializing GM crops.