A French nun who witnessed the execution of a Catholic priest by Islamist killers in Normandy, France yesterday has described how the killers gave an Arabic sermon at the altar and filmed the killing. Agence France Presse reports: A French jihadist who was under house arrest on terror charges took part in a church attack in which a priest was killed Tuesday, further inflaming tensions over security failures in the violence-weary nation. Adel Kermiche, 19, was one of two attackers who stormed a Catholic church in the northern town of Saint-Etienne-du-Rouvray during morning mass, slitting the throat of an 86-year-old priest, Jacques Hamel, and leaving a worshipper with serious injuries, said Paris prosecutor Francois Molins. The attack, claimed by the Islamic State group, comes with France still in mourning less than two weeks after Tunisian Mohamed Lahouaiej Bouhlel ploughed a truck into a crowd in the Riviera city of Nice, killing 84 people and injuring over 300. The carnage, the third major strike on France in 18 months, prompted a bitter political spat over alleged security failings and revelations over the church attack were likely to raise further questions. Molins said that Kermiche first came to the attention of anti-terror