The Humboldt 7 massacre was the extrajudicial killing of four unarmed Directorio Revolucionario Estudiantil (DRE) members by the Havana police on 20 April 1957. The police, led by Lt. Colonel Esteban Ventura Novo, entered apartment 201 of Humboldt 7, a residential building where the DRE members were hiding. The four men who were killed during the incident had taken part in the Havana Presidential Palace attack and the seizure of the Radio Reloj station at the Radiocentro CMQ Building.