BROOKLYN CENTER — A pair of ruby slippers used in “The Wizard of Oz” and later stolen from a Minnesota museum were recovered in a sting operation after a man approached the shoes’ insurer and said he could help get them back, the FBI said Tuesday.

The slippers were on loan to the Judy Garland Museum in the late actress’ hometown of Grand Rapids, Minnesota, when they were taken in 2005 by someone who climbed through a window and broke into a small display case. The shoes were insured for $1 million.

The FBI said a man approached the insurer in summer 2017 and said he could help get them back. Grand Rapids police asked for the FBI’s help and after a nearly year-long investigation, the slippers were recovered in July during a sting operation in Minneapolis.

The FBI said no one has yet been arrested or charged in the case, but they have “multiple suspects” and continue to investigate. As they unveiled the recovered slippers at a news conference Tuesday, they asked anyone with information about the theft to contact them.

“We’re not done. We have a lot of work to do,” Christopher Myers, the U.S. attorney for North Dakota, said.

Myers said he would handle any prosecution. The North Dakota link to the case wasn’t evident and authorities declined to explain it.

The slippers had been on loan to the Garland museum from Hollywood memorabilia collector Michael Shaw. Three other pairs that Garland wore in the movie are held by the Academy of Motion Picture Arts and Sciences, the Smithsonian and a private collector.

The stolen slippers’ authenticity was verified by comparing them with the pair at the Smithsonian’s Museum of American History in Washington.

The ruby slippers are key in the 1939 movie. After mysteriously landing in the colorful Land of Oz after a tornado hit her farm in Kansas, Garland’s character, Dorothy, has to click the heels of her slippers three times and repeat “there’s no place like home” to return.

Rhys Thomas, author of “The Ruby Slippers of Oz,” called the slippers “the Holy Grail of Hollywood memorabilia.”

“They are maybe the most iconic cinematic prop or costume in movie history, and in fact, in cultural history,” Thomas said. “They are a cultural icon.”

Thomas estimated that this particular pair could be worth between $2 million to $7 million. He said it’s not clear in which scenes they were used, but he was “99 percent” sure that they appeared in the film.

Thomas said the slippers then went unseen for 30 years until Shaw, acting as a middleman, bought them for someone who intended to sell them to the late actress Debbie Reynolds, but Shaw ended up keeping them and often loaned them for exhibits.

Law enforcement offered a $250,000 reward early in the case, and a fan in Arizona offered another $1 million in 2015.

The shoes are made from about a dozen different materials, including wood pulp, silk thread, gelatin, plastic and glass. Most of the ruby color comes from sequins but the bows of the shoes contain red glass beads.

The genre-busting Wizard of Oz — presented in black and white, and color — was a box office smash and was nominated for multiple Academy Awards, with wins for Best Song and Best Original Score.

Garland, who was born Frances Gumm, lived in Grand Rapids, about 200 miles (320 kilometers) north of Minneapolis, until she was 4, when her family moved to Los Angeles. She died of a barbiturate overdose in 1969.

The Judy Garland Museum, which opened in 1975 in the house where she lived, says it has the world’s largest collection of Garland and Wizard of Oz memorabilia.