Three works of religious art were stolen from two churches in the Spanish city of Valladolid, the latest in a string of thefts from museums and churches across Spain and Europe.

Two works disappeared from the Church of San Pablo: a small Station of the Cross depicting Jesus falling for the second time, decorated with a silver relief, and a 17th-century copy of an Ecce Homo by Spanish Renaissance painter Luis de Morales. A nearby church, Vera Cruz, meanwhile lost a roughly two-foot-tall polychrome wooden carving of an angel carrying a torch, according to El País.

The thefts occurred only days apart, and authorities are investigating whether the same person was responsible. The prior of San Pablo suspects its two works were taken during an evening Mass on September 10, while parishioners were facing the altar. A sacristan told the local newspaper El Diario de Valladolid that several people saw a man leaving the church carrying a large plastic bag. Church officials initially discovered that the Ecce Homo was gone and reported the theft, only to realize later that the Station of the Cross had disappeared as well.

The Archbishopric of Valladolid has since asked churches throughout the archdiocese to exercise “extreme precautions and surveillance” and urged them to keep updated inventories, preferably with photographs, of their holdings. It has also encouraged churches and religious orders to report suspected thefts as quickly as possible.

The Valladolid thefts come amid a notable run of robberies targeting art and antiquities. This summer, 220 19th-century gold coins were stolen from the Provincial Museum of Albacete, while 149 coins belonging to the so-called Villanueva Treasure were taken from the Provincial Archaeological Museum of Badajoz in April. More recently, pieces from the Bronze Age Treasure of Villena were stolen from a museum in Alicante.

Then there are the ancient Celtic gold coins that were stolen from a museum in Germany, the $4.5 million jewelry heist from a French museum devoted to the Decorative arts, and, most famously, the Louvre heist, a smash and grab job worth more than $100 million in royal jewels.

Europol, unsurprisingly, has noticed the trend. Jean-Yves Goriou, head of the European Union’s organized crime unit, told El País that the agency had observed “a clear and pronounced increase in the number of museum robberies” reported by national authorities, with gold objects particularly attractive to thieves because of the metal’s high market price.

Churches are a particularly easy target. They can sit nearly empty for hours at a time, and during services, the people who are there tend, quite reasonably, to be looking at the altar rather than keeping watch over the art. In Valladolid, that may have been all the opening the thief needed.