More than 70 stolen antiquities, some more than 2,000 years old, were seized from collections in the U.S. and returned to their native countries of Italy and Egypt this week.

The prized items included a mummy portrait, a marble head of the goddess Athena, and an intricately painted drinking cup.

Their return came after a string of search warrants enacted by the Manhattan District Attorney that targeted private collectors as well as The Metropolitan Museum of Art in Manhattan.

Of the 74 antiquities, valued at more than $22 million, 27 were seized from The Met, according to statements from authorities.

"[The] pieces represent thousands of years of rich history, yet traffickers throughout Italy utilized looters to steal these items and to line their own pockets," District Attorney Alvin L. Bragg, Jr. said of the pieces returned to Italy this week. "For far too long, they have sat in museums, homes, and galleries that had no rightful claim to their ownership."

Erin Thompson is a professor of art crime at the City University of New York and said there was no question about whether the artifacts were stolen or not, but getting entities like the Met to admit it had been a work in progress.

"Right now the museums are just waiting for authorities to approach them and say there's a problem with this particular item," she said. "But the museums have all of this information about items in their collection, why aren't they the ones digging into this information?"

Thompson said that in the case of these 74 antiquities, there was one prolific smuggler at the center who was caught by Italian authorities decades ago. After seizing his records, they were able to determine many pieces that had passed through his ring.