MOSCOW (AP) — A Russian Orthodox Church panel looking into the 1918 killing of Russia's last czar and his family says it's investigating whether it was a ritual murder — a statement that has angered Jewish groups.

Father Tikhon Shevkunov, the Orthodox bishop heading the panel, said after Monday's session that "a large share of the church commission members have no doubts that the murder was ritual." A representative of Russia's state investigative agency said it will also probe the theory.

Rabbi Boruch Gorin, a spokesman for the Federation of Jewish Communities, on Tuesday expressed concern about the claims he described as part of anti-Semitic propaganda, according to Interfax.

Nicholas II and his family were executed by a Bolshevik firing squad in July 1918. The Russian Orthodox Church made them saints in 2000.