The family of the female saleswoman stated.
When she left, she only brought 5 sets of gold and jade gifts.
And she gave all these 5 sets to the five people at that meal.
Since all five of them had gold and jade gifts, it meant that the person at the crime scene wasn't among them, and it was very likely an inter-provincial customer.
However, expanding the scope to inter-provincial customers not only made the range too wide, but also made cross-provincial investigations much more complicated. By the time they had sufficient evidence, the real perpetrator among these five would have long fled.
Citizens have the duty to cooperate with the investigation, but without any substantive evidence, they cannot impede citizens from conducting their normal business.
This was exactly the problem that Du Huansheng was fretting over now.
The case could be investigated and would be solved sooner or later.