The 4th of August Party (K4A; Greek: Κόμμα 4ης Αυγούστου, romanized: Kómma 4is Avgoústou, [ˈkoma teˈtartis avˈɣustu]) was a radical Greek Metaxist political party, founded in July 1965 by a group of young nationalists and led by Konstantinos Plevris, a self-confessed "Nazi, fascist, racist, anti-democrat, anti-Semite".

On 24 February 1977, Aristotelis Kalentzis, a member of the party, was arrested along with others for possession of explosives and weapons in an apartment in Kato Patissia.

In retaliation, comrades of those arrested responded with a barrage of bombings targeting left-wing organizations and publications in the Athens area.

Kalentzis, later incarcerated in the prisons of Nea Alikarnassos initially and then of Corfu and describing himself as a "political prisoner", openly and publicly accused Plevris of being an informant for the National Intelligence Service through his book Democracy 80.

Kalentzis essentially claimed that Plevris trapped him, "selling" him to the police authorities, as he did with other comrades.