Sabotage

Sabotage is a deliberate action aimed at weakening a polity, effort, or organization through subversion, obstruction, disruption, or destruction. One who engages in sabotage is a saboteur. Saboteurs typically try to conceal their identities because of the consequences of their actions and to avoid invoking legal and organizational requirements for addressing sabotage.

A United States poster from the World War II-era that was used to inform people about what they should do if they suspect sabotage