Muna93:
yes he's very suspicious
i think the caretaker is the ghost mom
i think the ghost have an assistant and shes yoo Ryung sister
LakshP:
Kim Woo Hyuk (Ma Ri's Partner) looks suspicious. He keeps on suggesting Yoo Ryung (YR), not to enter the tunnel, and that too avoiding the other detectives. He might not be the killer - spasms.....but he definitely seems suspicious. Plus another character who might be linked to the ghost is the hospital caretaker.....she was s**t scared when she saw the video on phone (ep 5)
But in the last Ep the ghost appears to kill the girl "who lost her bag" and the 4 characters were together in the station!!