The Christian family behind the arts and crafts chain Hobby Lobby has been under federal investigation for years on suspicion of trying to import potentially illicit cultural artifacts from Iraq, The Daily Beast reported late Monday.

Anonymous law enforcement sources told the publication that for the past four years the Green family, whose prior claim to fame was a successful lawsuit before the U.S. Supreme Court for relief from Obamacare’s contraception mandate, has been under investigation for “the illicit importation of cultural heritage from Iraq.”

The investigation was triggered by a shipment of 200-300 clay tablets that U.S. customs agents seized in 2011 en route from Israel to Oklahoma City, according to the report. An anonymous senior law enforcement source told The Daily Beast that the tablets were purchased and imported by the Green family; it’s unclear why that information only is being revealed now.

Those tablets were bound for the Greens’ non-profit Museum of the Bible, which is scheduled to open in Washington, D.C. in 2017, according to the report. The museum’s president, Cary Summers, confirmed to The Daily Beast that that the tablets were seized and that they were part of a federal investigation.

Summers downplayed the investigation as a result of “incomplete paperwork” in an interview with The Daily Beast. But Hobby Lobby CEO Steve Green said his family’s antiquities collection, which includes approximately 40,000 artifacts, may include items that the family unwittingly acquired through illicit means, according to the report.

“Is it possible that we have some illicit [artifacts]? That’s possible,” he said, as quoted by The Daily Beast.

Read the whole thing here.