I have read hundreds of books and watched many movies and documentaries about the dirty wars of South America, the most notorious being the Pinochet regime in Chile. The recurrent feature in all those stories is the case of disappearing men and women, abducted, tortured and murdered by the security forces.
The story is always the same, it's justified as the war against the communists, terrorists, the guerillas or some similar dark excuse. But ultimately there is no justification for such violent actions. Ultimately, such tactics do not enhance democracy or strengthen security. In fact, countries that use such tactics end up with authoritarian regimes with no respect for human rights or rights of any kind.