After thanking the manager, Xiaotao, Song Xingchen and I left the motel house. 

"Why the suspense? How did they do it?" Xiaotao asked impatiently.

"I’m just afraid others might hear us. It's quite simple actually. They painted a layer of nail polish on the fuse."

"Nail polish?" Xiaotao looked confused.

If the voltage was too high, the fuse would burn when it reached the melting point, which was about 500 degrees. The suspects coated the fuse with transparent nail polish. Since the melting point of nail polish was only 300 degrees, when the voltage reached a certain level, it burned up, so the capacitor was burned out, and so did the fuse. But laymen wouldn’t be able to tell.

The...