In the south of Italy, Matera is known as the “City of Stones” for its architecture.

Pope Francis has traveled to southern Italy to close out an Italian church congress that coincided with Italy’s national election.

The vacationing 15-year-old girls, who spoke no Italian, met the male suspects at the party they attended with the adult sister of one in the southern province of Matera. Police said two of the young Italian males won their trust by acting in a friendly manner while also taking advantage of the girls' “altered state” from consuming alcohol. As the party of about 50 people went on inside the villa, the adult sister lost sight of the girls, investigators said. Police said the two girls were then sexually assaulted, in separate attacks that lasted about 15 minutes. The four arrested were positively identified by the girls, according to police, while three others were identified from the video.