Jiang Yuan simply pulled over a whiteboard and drew the shape of a keyhole on it, then marked a few dots and said: "We disassembled the lock because, in my opinion, there were too many scratches inside the keyhole, exceeding the level of a normal lock. Of course, this judgment is based on experience... Next, we took a wide range of samples, and then we could see that the presence of various metal elements inside the lock was beyond the normal range."
If a young technician had said this, it would definitely be hard to convince others, but when Jiang Yuan said it, Liu Jinghui immediately followed his line of thought.
"Let me get this straight... The metal elements you mentioned, are they brought in by the key, not originally part of the lock?" Liu Jinghui quickly grasped the important point.
