From a Wired article about a brilliant thief:
Blanchard wasn’t listening. He was noting the motion sensors in the corner, the type of screws on the case, the large windows nearby. To hear Blanchard tell it, he has a savantlike ability to assess security flaws, like a criminal Rain Man who involuntarily sees risk probabilities at every turn. And the numbers came up good for the star. Blanchard knew he couldn’t fence the piece, which he did hear the guide say was worth $2 million. Still, he found the thing mesmerizing and the challenge irresistible.
He began to work immediately, videotaping every detail of the star’s chamber. (He even coyly shot the “No Cameras” sign near the jewel case.) He surreptitiously used a key to loosen the screws when the staff moved on to the next room, unlocked the windows, and determined that the motion sensors would allow him to move — albeit very slowly — inside the castle. He stopped at the souvenir shop and bought a replica of the Sisi Star to get a feel for its size. He also noted the armed guards stationed at every entrance and patrolling the halls.