The Jilava Massacre took place during the night beginning on November 26, 1940, at Jilava penitentiary, near Bucharest, Romania. Sixty-four political detainees were killed by the Iron Guard (Legion), with further high-profile assassinations in the immediate aftermath. Coming about halfway through the fascist National Legionary State, it led to the first open clash between the Guard and conducător Ion Antonescu, who would oust the former from power in January 1941.
Under King Carol II, repressive measures against the Iron Guard gathered pace in the late 1930s; a cycle of violence on both sides left many dead, including Prime Minister Armand Călinescu and Corneliu Zelea Codreanu, the Guard's founder and leader. After Carol abdicated in September 1940 and the Guard ascended to power, its members thirsted for revenge, seeking to eliminate those who had participated in the various legal and illegal actions taken by the king's regime. The more restrained Antonescu sought punishment through legal means. Within his first month in power, he approved an official probe into all those who could not account for becoming wealthy very fast in the last years of Carol's rule, and established a special court to investigate crimes committed by the previous regime's principal figures, or in their name, against the Guard.
The court ordered the arrest of those to be investigated, had them imprisoned at Jilava, and entrusted them to the custody of special Legionary formations, described by Alexandru Creţianu as "nothing less than an improvised version of the SS strong-arm squads".
The investigation underway, the court, wishing to obtain testimony from the detainees in order to prepare for their trials, ordered several of them to be transferred to another jail, where their depositions would be taken. However, Ştefan Zăvoianu, the Bucharest Prefect of Police in charge of the Legionary squads guarding the prisoners, believed Antonescu had changed his mind about executing those responsible for Codreanu's death and refused to comply with the order. This alerted the military authorities, who decided to replace the squads with regular military guards and move the prisoners themselves. Zăvoianu was informed of this decision on November 26, and that night the squads shot dead every one of their charges: politicians, senior military officers, and policemen accused of complicity in Codreanu's arrest and execution.