Harry Potter Prequel Stolen!!

J.K. Rowling is warning 'Harry Potter' fans not to shell out any Galleons for a handwritten prequel that fell off the back of a broom ... as in, it was stolen.

The burglary happened last month in Birmingham, England at the home of someone who purchased the prequel at a 2008 charity auction for about $40k. It's a pretty cool piece of Potter history -- 800 words written on a postcard that lay out the story of Harry's pop, James Potter, and godfather, Sirius Black, as teenagers.

Cops still haven't made any arrests, but J.K. made a plea Friday to her 10 million followers. Just a matter of time till someone whips out the Probity Probe and finds it, we're guessing.