As soon as he mentioned it, he took it to heart, and immediately suspected Meng Shaomei, because she was the one who gained the most from the death of Dong Anni and Su Xingmo. He had his people keep an eye on her, and they were indeed able to find a clue. At the same time, they started looking for the driver who used to drive for Su Xingmo.
Su Xingmo was the sole heir of the Su's then. With such an identity, he shouldn't have been driving, but it would not be too strange if he ran off privately without a driver. But Murong Che doesn't think the two of them eloped. After investigation, it was found that whenever Su Xingmo went somewhere, it was the driver who took him. Even when he picked up Dong Anni, it was the driver who drove. Why then, did the driver disappear all of a sudden?
He felt that finding the driver would bring him one step closer to the truth, so he had people investigate Su Xingmo's driver from that year.