A new and nefarious connection between criminal networks and jihadi groups is potentially emerging across the Mediterranean, according to Italian police.

Authorities in Rome are investigating links between the country’s mafia criminal organizations and the Islamic State militant group (ISIS), suspecting them of possibly working together to smuggle oil into Europe.

The police force has discovered quantities of oil in the country that exceed the amount some Italian refineries can hold, according to an article in the print edition of Italian newspaper La Repubblica. They believe the contraband oil was imported from Syria and Libya, both countries where ISIS militants maintain a presence.

The report cites a confidential February 2017 report of the Special Police Headquarters of the Guardia di Finanza, a law enforcement agency that reports to the Ministry of Economy and Finance.