Luckily, Jing Yunyao's face wasn't clear in the surveillance videos, so they failed to recognize her. In addition, they believed that Jing Yunyao was already dead, so they didn't think the woman could be her.
After all, it was very common that cultivators who often visited mortals' world had a few friends there, so it wasn't a problem that cultivators met mortals. However, because Jing Jining met the woman right before seeing Yin Shixun, they were suspicious of the woman and thought that she might have something to do with Yin Shixun's death.
It was one of the possibilities they could think of, but it didn't mean that they believed Jing Yunyao was guilty.
Besides, they weren't sure whether Yin Shixun died on the day when he met Jing Jining and they all knew that Jing Jining wasn't as skilled at Yin Shixun, so they were doubtful about Jing Jining's involvement in Yin Shixun's death even if they were aware of their bad relationship.