JK Rowling begs fans not to buy stolen 'Harry Potter' prequel

— -- An extremely rare "Harry Potter" prequel idea, handwritten by best-selling author J.K. Rowling, has been stolen. And the author is pleading with fans not to purchase it on the black market.

According to England's West Midlands Police, the 800-word story was handwritten on the front and back of an A5 postcard. It was stolen during a robbery in central England, sometime between April 13 and April 24.

Rowling hand wrote the story to raise money for English Pen, an organization that promotes literature. It sold at a charity auction for £25,000 or approximately $32,000, in 2008.

Investigating Officer PC Paul Jauncey said in a statement, "The only people who will buy this unique piece are true 'Harry Potter' fans. We are appealing to anyone who sees, or is offered this item for sale, to contact police."

Rowling, 51, appealed to fans today, as well.

"PLEASE DON'T BUY THIS IF YOU'RE OFFERED IT," she wrote emphatically on Twitter. "Originally auctioned for @englishpen, the owner supported writers' freedoms by bidding for it."

Police are still searching for the rare story and are asking "Harry Potter" fans to "please call 101" in England if they had leads, according to a tweet.