No, the jihadists weren't praying the rosary; the Catholics were. Islamic tolerance alert: "Islamic extremists attack Catholics reciting rosary," from [1] AsiaNews, with thanks to Twostellas:

Jakarta (AsiaNews) – A group composed of Islamic extremists attacked Catholics praying the rosary on 11 October and threatened to burn down the house they were gathered in. The assailants, who claimed to be part of the Islamic Defender Front (Front Pembela Islam, FPI), invaded the house of one of the Catholic community belonging to the parish of Christ Salvator in western Jakarta.

The men forced the marian prayer to stop immediately, threatening to burn the place down. They forced all those present including the Ketua Lingkungan (informal parish leader - ed. note) to sign a declaration that they will not hold any more rosary gatherings in houses in the area.