Got The Scoop On The Gardner Museum Art Heist? You Have 4 Days To Earn $10 Million

If you've got a burning secret about the 13 pieces of art missing from Boston's Isabella Stewart Gardner Museum, the clock is ticking.Share the details in the next four days, and you'll earn a cool $10 million.Wait until 2018, and that reward will be slashed in half. The 1990 theft of the masterpieces was the biggest-ever heist from an art museum and the largest property crime America has ever seen. Three Rembrandts, including his only known seascape. A Vermeer. A Manet. Sketches by Degas. All spirited away by bold thieves disguised as policemen.The artworks are, collectively, worth more than $500 million, but they're so recognizable that they're believed to be nearly impossible to sell. No one knows where they are.Twenty-seven years later, the museum has empty frames on its walls — reminders of the art that isn't there. A $1 million reward was later boosted to $5 million. And this year, the prize money was doubled, with a deadline of Dec. 31. As the deadline approaches, museum spokeswoman Kathy Sharpless told CBS News the museum is "laser-focused" on that date. "Clearly there's a sense of urgency on our part," she said. "We want our paintings back."To be clear, the museum isn't looking for the names of the thieves. The FBI actually has a pretty good idea who did it — they suspect two men tied to the mob — but the statute of limitations on the crime expired years ago. It's not about catching the crooks or making sure justice is served. The museum just wants its masterpieces back. Anthony Amore, head of security at the museum, tells ABC News that the increase in prize money did rev up some fresh interest from the public."We received a number of good leads, good calls from concerned citizens and lots of theories from people as well, but as you can imagine we're not interested in theories," Amore told ABC. "We're just interested in facts that lead us to a recovery." If you have those kinds of facts at hand, email theft@gardnermuseum.org to pass along your tip — confidentiality guaranteed — and claim your $10 million. Curious about how that grand heist went down? Boston Globe reporter Stephen Kurkjian, author of a book about the theft, explained the night's fateful events to NPR in 2015. "Two men dressed in police uniforms rang the bell to the employees' entrance of the Isabella Stewart Gardner Museum. They showed up on the monitor screen of one of the two night watchmen who were on duty that night. ... They said, 'We're here to investigate a disturbance,' so [security guard Rick Abath] buzzed them in. "He stepped away from the security desk that he was sitting at, and that removed him from the only alert. The only outside alarm that the museum had was a button that was at his security desk. And he stepped away from it because the alleged police officers, the thieves, said to him that he 'looked familiar,' that 'didn't they have a warrant out for his arrest?' "He was worried that if he was arrested on a weekend night — and this was Sunday morning — he would not be in court until Monday, and he knew he had tickets to that night's Grateful Dead concert in Hartford, Conn. And he didn't want to miss it by being in jail, so he stepped away and he got tied up, he got apprehended. His fellow night watchman came down and they tied him up and then, you know, these two thugs were allowed to pull off the greatest art theft — half a billion dollars ... probably more. "No one can put a value on these paintings because no one's going to buy stolen artwork of this value. And that's why the sense is that the works do not lay in the hands of an art collector who cannot live without this Rembrandt or that Vermeer but they were stolen for some other reason."That security guard who let the thieves in, Rick Abath, shared his memories of that night on StoryCorps in 2015. He remembered being handcuffed to the electrical box in the museum for eight hours, duct tape over his eyes, singing Bob Dylan's "I Shall Be Released" over and over again."I was just this hippie guy who wasn't hurting anything, wasn't on anybody's radar," he said. "And the next day, I was on everybody's radar for the largest art heist in history." "Two of the Rembrandts, they cut them out of the frames. So even if they get the paintings back, they'll never be the same," he said. "And I feel horrible about that ... ultimately, I'm the one who made that decision to buzz them in." Copyright 2017 NPR. To see more, visit https://www.npr.org/.