Actually, this matter is easy to handle.
Prince Lu instructed the Prefect of Mingzhou to pretend to impeach Meng Su and search for evidence everywhere.
This matter would inevitably reach Meng Su's ears. If it were someone else, Meng Su might be suspicious and wonder if it was his spy, but the Prefect of Mingzhou was different. The Prefect of Mingzhou had a well-known reputation, had no errors while in office, and was fairly close to Meng Su. Many times when Meng Su submitted memorials to the court, the Prefect of Mingzhou supported him from the side.
Additionally, the two of them came from the same exam rank, and they had mutual appreciation for each other. In Meng Su's mind, Prefect Zhao was an indisputably good official.
