Federal authorities announced charges against a ring of nine people for theft of millions of dollars worth of paintings, sports memorabilia and other valuables including an Andy Warhol silkscreen, a Jackson Pollock painting, and nine World Series rings belonging to the late Yankees catcher Yogi Berra.

The thefts took place over more than two decades at 20 museums, institutions, and stores across Pennsylvania, New Jersey, New York, Massachusetts, Rhode Island, Washington, DC, and North Dakota, the US attorney for the Middle District of Pennsylvania said Thursday .

Investigators believe some of the sports memorabilia and other items have been melted down, including nine of Berra’s 10 World Series rings, US Attorney Gerard M. Karam said at a news conference.

It was unclear which items would be returned to their owners or to the museums, but authorities said some of those valuables had been recovered.

Eight of the nine people named as part of the theft ring Thursday have turned themselves in, Karam said. At least five had already entered into preliminary plea agreements on charges of theft of major artwork and conspiracy to dispose of major objects of cultural heritage, according to court records. The suspects are in their late 40s to early 50s and are Pennsylvania residents.

Phone messages were left Thursday for attorneys listed in court documents as representing those eight suspects. Two of those attorneys said they could not comment at this stage of the case.

Karam said the ninth suspect, 53-year-old Nicholas Dombek, is considered a fugitive.

The accused allege the thieves transported the memorabilia and valuables and would melt the silver and gold items down into transportable discs that were sold for hundreds of thousands of dollars — but for much less than many of the items were worth.

The indictments also note that a handful of the suspects were involved in each break-in, casing security at targeted museums, planning, and then one or two people executing the actual thefts. The suspects would then sell and trade items with the larger group, according to court records.

Court documents also allege that Dombeck destroyed a painting by Jasper Cropsey, burning it to avoid the stolen artwork entitled “Upper Hudson” from being used as evidence against him.

Some of the thefts happened nearly 20 years ago, including the 2005 theft from the Everhart Museum in Scranton, where the thieves shattered a glass door in the back of the building. They stole a 1949 oil-on-canvas painting by Jackson Pollock, “Springs Winter,” then worth an estimated $11.6 million, and a silkscreen by Andy Warhol titled “Le Grande Passion,” then worth an estimated $15,000, but listed in the said as having a value of about $100,000.

Karam provided few details of how investigators from the FBI to local police departments cracked the case, saying only that evidence uncovered recently unraveled the ring’s activities.

“About three years ago, a forensic link at one of the theft sites discovered by a local police agency led us to forensic evidence that linked several of these thefts,” he said.

Details of the stolen items included:

— A baseball jersey from New York Giants pitcher and Hall of Famer Christy Mathewson, as well as two contracts he had signed that were on display at Keystone College.

— Nine World Series rings, seven other rings, and two MVP plaques belong to Yogi Berra, including the rings believed to be melted down and destroyed.

— A Hickok Belt — solid gold and encrusted in jewels — and MVP plaque from the Roger Maris Museum in Fargo, North Dakota. Maris won two MVP awards, including when he passed Babe Ruth’s single-season record with 61 home runs in 1961 for the Yankees.

— A Hickok Belt and US Amateur Trophy awarded to Ben Hogan, from the USGA Golf Museum and Library. Hogan, a nine-time major champion, is one of the greatest and most influential golfers in the sport’s history.

— Twelve trophies awarded to golfing great Art Wall Jr. that had been on display at the Country Club of Scranton, Pennsylvania, are believed to have been melted down and destroyed.

— $300,000 worth of trophies from the National Harness Racing Museum in Goshen, New York.

— An 1836 Colt Paterson revolver and two other guns from the Space Farms Zoo and Museum in Wantage, New Jersey.

Other thefts prosecutors connect to the charges released Thursday occurred at the Boxing Hall of Fame, the Sterling Hills Mining Museum, Ringwood Manor, and other facilities. Other stolen items included gold nuggets, gems, paintings, firearms, historical objects, and sports prizes.

By ting