Three eco-terrorists were found guilty in Switzerland Friday for their involvement in a foiled plot to blow up an unfinished IBM nanotech research center near Zurich.

The verdict in Switzerland's highest criminal court found Costantino Alfonso Ragusa, his wife Silvia Ragusa Guerini and their Swiss friend, Luca “Billy” Cristos Bernasconi, guilty of conspiring last year to destroy the research facility as it neared completion.

They were each sentenced to more than three years in jail, a slightly longer prison term than prosecutors had sought.

Police arrested the trio in April 2010 when they were stopped with explosives and bomb-making materials in their car.

Police also found dozens of letters claiming responsibility for the planned attack, signed by “ELF Switzerland, Earth Liberation Front,” which stated a goal of stopping the destruction of the environment.

Security was tight during the trial this week at the Federal Criminal Court in the southern Swiss city of Bellinzona. At least 50 supporters of the defendants gathered with signs and loudspeakers outside the courthouse to demand their freedom.