The territorial gains made by the Islamic State in Iraq and Syria have provoked fears — as well as tentative news reports — that archaeological sites in those countries are being attacked and looted, much as sites in Iraq were at the outset of the second Iraq war.

We have recently returned from southern Turkey, where we were training Syrian activists and museum staff preservationists to document and protect their country’s cultural heritage. That heritage includes remains from the ancient Mesopotamian, Assyrian, Hellenistic, Roman, Byzantine and Islamic periods, along with some of the earliest examples of writing and some of the best examples of Hellenistic, Roman and Christian mosaics.

In extensive conversations with those working and living in areas currently under ISIS control, we learned that ISIS is indeed involved in the illicit antiquities trade, but in a way that is more complex and insidious than we expected. (Our contacts and sources, whom we cannot name out of concern for their safety, continue their work under the most dangerous of conditions.)

ISIS does not seem to have devoted the manpower of its army to the active work of looting archaeological sites. Rather, its involvement is financial. In general, ISIS permits local inhabitants to dig at these sites in exchange for a percentage of the monetary value of any finds.