For two decades, a crew from Lackawanna County in Pennsylvania traveled to a dozen small museums across the country, where its ringleader smashed through security systems to strip them of art and precious memorabilia.

Their loot included treasured heirlooms from America’s past, including nine of Yogi Berra’s World Series rings, two of middleweight Tony Zale’s championship belts and 30 golf and horse racing trophies. Instead of selling the memorabilia, they melted much of it down and sold it as raw metals.

On Friday, three men involved with the theft ring were convicted in U.S. District Court in Scranton, Pennsylvania, of conspiracy to commit theft of major artwork.

The convictions followed testimony from the former ringleader of the group, Thomas Trotta, who pleaded guilty and became a central witness at the trial of the men, who had been his friends since middle school. According to prosecutors, Trotta broke into the museums, while the other men assisted him by either planning the robberies, melting down the items or transporting them.

— The New York Times