Why didn't Wei Zi Shentan write?

It seems that the author of Detective Wei Zi didn't continue writing after finishing the fourth book. It is said that the author may encounter difficulties in writing, or he may have other problems that prevent him from continuing his creation.

In addition, for the stagnation of some novels, sometimes it may be that the author has no intention to continue writing, or the story has reached a relatively complete ending and there is no need to continue writing.

However, these are only speculations, and only the author himself can give the most accurate answer.