He was released on his recognizance, but arrested 10 days later. He was accused of acting as an undercover liaison between Fatah, the dominant faction within the Palestine Liberation Organization, and guerrilla cells in the West Bank.
The authorities also said he had smuggled gold, whiskey and television sets across the border.
In addition, investigators said the archbishop had been involved in a plan to fire three Katyusha rockets toward Jerusalem during a May 1974 visit by Secretary of State Henry A. Kissinger. (The rockets were discovered before they went off.)
He was the highest-ranking Christian clergyman ever to be charged by Israel with such crimes, and the arrest made headlines. Yasir Arafat, the P.L.O. chairman, called the arrest “a terrible crime.” The Vatican noted it “with great sorrow.” The archbishop’s supervisor, Maximos V Hakim, the Melkite Greek patriarch of Antioch, petitioned for his release and flew to Rome to discuss the situation with Pope Paul VI.
The Israeli authorities, who had kept the archbishop under surveillance for some time, were unmoved. They said he would stand trial and then indicted him on charges that included maintaining contact with foreign agents and carrying illegal weapons. Prosecutors said he had met with Khalil al-Wazir, a top militant known by the nom de guerre Abu Jihad, and another militant at the home of the archbishop’s relatives in Beirut.
As the case moved toward trial, the Israeli Army said it had foiled an Arab terrorist plot to free the archbishop from jail. A judge rejected the archbishop’s claim of diplomatic immunity, noting that Israel and the Vatican did not have diplomatic ties. (Full relations were not established until 1993.) Archbishop Capucci refused to take the stand, insisting that the court was not competent to try him.
On Dec. 9, 1974, he was sentenced to 12 years in prison. Addressing the court, he said in Arabic that if Jesus were alive they would have wept together.
Archbishop Capucci was given a one-person cell and permitted to celebrate Mass and wear his clerical robe. He was allowed visitors, including the Latin patriarch of Jerusalem.
On June 28, 1976, militants hijacked an Air France plane en route from Tel Aviv to Paris, diverted it to Entebbe, Uganda, and demanded that Israel release 40 prisoners, all of them Palestinians or supporters of their cause, including Archbishop Capucci. A week later, Israeli commandos rescued the hostages in a nighttime mission at the Entebbe Airport.
Archbishop Capucci’s time in prison came to an end in 1977, after elections that brought the right-leaning Likud Party to power. The new government said it would be willing to release him if the pope made a formal request. The pope requested his release on humanitarian grounds — he had been on several hunger strikes — and on Nov. 6, his sentence was commuted. He was put on a commercial flight to Rome, where he was met at the airport by a P.L.O. delegation.
The release stipulated that Archbishop Capucci not be reassigned in the Middle East, and after an audience with the pope, he was sent to Latin America. He irritated the Vatican when, in January 1979, he went to Damascus to attend a meeting of the National Council of the Palestine Liberation Organization, of which he was a member. Nonetheless, Pope John Paul II transferred the archbishop to Western Europe later that year.
Archbishop Capucci maintained his activism in the region. He visited Americans held captive at the United States Embassy in Iran in 1979; accompanied the bodies of eight United States service members who were killed in an unsuccessful mission to free the hostages; and traveled to Iraq in 1990 to petition Saddam Hussein’s government to release a group of Italians after the invasion of Kuwait.
He was on board a Turkish-owned ship, part of a 2010 attempt to send relief to the blockaded Gaza Strip, when it engaged in a clash with Israeli forces.
Hilarion Capucci was born on March 2, 1922, in Aleppo, Syria, which was then under French control. He was ordained a priest in 1947 and appointed patriarchal vicar of Jerusalem and titular bishop of Caesarea in 1965.
In a 2010 interview with Al Jazeera, he said he had taken part in the Gaza aid effort “to meet the tortured, persecuted and wronged kinfolk in the strip to assure them that we are with them morally and spiritually.” He said his goal was “to establish a free, sovereign, independent state, with Jerusalem as its capital.”
An earlier version of this article referred incorrectly to the location of Nazareth. It is in northern Israel, not in the West Bank.