In 1941 several members of TIGR were condemned for espionage and terrorism at the Second Trieste trial; four of them (Viktor Bobek, Ivan Ivančič, Simon Kos and Ivan Vadnal) were executed in Villa Opicina near Trieste the same year, jointly with the Communist activist Pinko Tomažič.
During World War II, many of its members joined the partisan resistance, although the organization itself was not invited to join the Liberation Front of the Slovenian People.