Searching old cases was something Jiang Yuan had done before.
Of course, when it comes to cases, it's not about seeking novelty or peculiarity; any method that leads to a successful case resolution is a good one. Who cares if it's been used before?
In fact, when normal police officers work on cases, they tend to reuse methods that have worked previously. Otherwise, using new, novel, and peculiar methods on significant cases may look impressive if successful, but what if it fails? The leaders of the detectives can scold really nastily, with both harshness and filth.
Jiang Yuan himself updated his skills rapidly, but those under his command didn't have such conditions.
People like Wang Chuanxing were even timid when looking into old cases, fearful of making a mistake or an omission that could cause a problem in the case under the supervision of the ministry.
