The Museum of Fine Arts is world renowned for its rare antiquities and sophisticated artifacts. What it’s not known for, however – and rightly so – is harboring stolen works from other countries. On Thursday, the MFA announced that it sent eight acquired pieces back to Nigeria after discovering they entered the U.S. art market in shady fashion.

According to WBUR, Victoria Reed, who holds the title of curator of provenance, gathered information and intelligence on each work’s authenticity and former ownership as part of her daily responsibilities. In fact, she does this for all “450,000 objects in the MFA’s collection.”

The museum noted in a statement that it “received the objects in the bequest of a local collector of African art, who acquired all eight objects in good faith in the 1990s from dealers in the United States and Europe.”

In researching the legitimacy of the art, the MFA contacted the National Commission of Museums and Monuments in Nigeria, which confirmed that the export of each piece had not been approved by the applicable authorities and the documents which authorized the sale to the museum were forged.

The Nigerian authorities received the works earlier in June.