
No, I believe he got caught on camera and someone in the Troupe was supposed to make sure that all CCTV data was tampered with in that area. They intentionally did not. However, once two of his friends, Nayoon and the one with the pharmacy company sees his photo at two different times, they recognized his stigma tattoo and knew he was the murderer.

He wasnt caught on camera. From what i remember, a troupe member was supposed to put up a barrier around the area where hajin killed nayoon's brother. This barrier will block all kinds of surveilance. But that member purposely let hajin's stigma(tattoo) be seen for a moment. Only the image of the stigma was discovered by yeonha's uncle(the one who investigated hajin's past before).

The stigma was seen by yeonha's uncle's Gift(seeing/tracing someone's past, he traced nayoon's brother). That member wanted an excuse to fight with yeonha's uncle(or was it nayoon's granfather, im not sure). The member suggested they get revenge for hajin but Boss shut that down because she found it suspicious.
It's interesting how they did this chapter compare to the novel