In the following days, Changyang City's Image Reconnaissance Brigade and the technical investigation team both got involved in the case investigation.
The residential district where Wang Xingzhai lived was still in a bustling part of the city, and there were a very large number of cameras, including those inside building elevators.
However, the killer kept his head down the whole time and wore a big mask, which greatly hindered the performance of image investigation. Some European countries had a ban on masks for a while, precisely to avoid the difficulty in image recognition.
Jiang Yuan also helped look at the gait; he managed to remember the gait, but when trying to match the gait to the person, if it was in real-time it would have been manageable, but with so many days having elapsed, tracking became difficult.