From Vatican Radio and other sources:
March 24th marks the Church’s day of prayer for missionary martyrs, in memory of Salvadoran Archbishop Oscar Romero who was murdered while celebrating Mass on that day in 1980.
During Romero’s beatification in San Salvador last May, March 24th was also recognized as his feast day, yet this year the date marks Holy Thursday and will therefore not be celebrated as an official saints day.
On March 24, 1980, Romero celebrated Mass in the chapel of Divine Providence Hospital. “Those who act out of love for Christ and give themselves to the service of others will live,” he told the small congregation, including nuns from a nursing order. Referring to the Eucharist he was about to celebrate, he said, “May this body immolated and this blood sacrificed for humans nourish us also, so that we may give our body and our blood to suffering and to pain — like Christ, not for self, but to bring about justice and peace for our people.”
Moments later, as he elevated the chalice filled with the Precious Blood, a gunman shot Romero from the back of the chapel. He died almost immediately.