Manga Like Shape of the Nightmare

Da-Eun Jeong and Jong-U Yun are the sole known survivors of two killing rampages perpetrated by a mysterious gang. Many years later, an investigation into a possible copycat crime forces them to revisit their trauma. Da-Eun becomes determined once again to find her boyfriend, Gyu-Heon Shim, who went missing after the murders they witnessed. Meanwhile, Jong-u is plagued by the ghost of “Room 203,” his former neighbor who came within inches of killing him. His sick brother Jong-Seok was his only reason for living, but with Jong-Seok now dead, will he help DaEeun? And will Gyu-Heon ever be found? (Source: WEBTOON, edited) Note: Includes one extra chapter.