"His Holiness Pope Francis was deeply saddened to learn of the tragic death of your son and brother, Steven Joel, and he has asked me to convey to you his prayerful condolences," said the Sept. 5 letter, signed by Cardinal Pietro Parolin, Vatican secretary of state.
"He entrusts Steven's soul to the Lord and offers prayers for you and all who mourn his death," the letter said.
"His Holiness urges people everywhere to reject violence, aggression and lack of compassion, and asks each one to pray and work for forgiveness, healing and peace," Cardinal Parolin wrote.
"Upon you and your loved ones, he invokes the Almighty's blessings of consolation and strength."
Cardinal Parolin asked Archbishop Carlo Maria Vigano, the Vatican nuncio to the United States, to relay the pope's condolence message to the bishop of the diocese in which Sotloff's relatives lived. That turned out to be the Archdiocese of Miami, where the message was entrusted to Archbishop Thomas G. Wenski.
The letter was posted on the archdiocesan website.
Sotloff, 31, who had both U.S. and Israeli citizenship, had been kidnapped a year ago in Aleppo, Syria. A video of his beheading was released Sept. 2 by Islamic State.
The beheading of another American journalist, James Foley, was released by ISIS Aug. 19, as apparent retaliation for U.S. airstrikes against ISIS. On the video, one of Foley's ISIS captors said the "next move" of President Barack Obama would determine Sotloff's fate. Airstrikes have continued. After the Sotloff beheading video was released, Obama said the United States would "degrade and destroy" ISIS.
Two days after the Foley beheading video was released, Pope Francis phoned the parents of the slain Catholic journalist.
Speaking Aug. 22 on NBC's "Today" show, Foley's father, John, said, "we felt very comforted and supported" that the pope offered his personal prayer.
Foley's mother, Diane, said, "Pope Francis was so dear because he is grieving himself, having just lost three members of his family and (with) his nephew critically ill."' She added, "Here in the midst of his tremendous grief, he took the time to call. Our whole family was there, one of our beloved priest friends ... was there, my brother-in-law spoke in Spanish to him. He was just so kind."
The wife and two young children of the pope's nephew, 35-year-old Emanuel Horacio Bergoglio, were killed in a car crash Aug. 19 in Argentina. Bergoglio was critically injured.