The House in Which Nightmares Dwell

Ghost Hunt follows the adventures of Kazuya Shibuya, the president of the Shibuya Psychic Research Center (SPR) and Mai Taniyama, a first year high school student. The story begins during an exchange of ghost stories between Mai and her friends, who are interrupted twice: first by a mysterious "male student" and then by a fellow classmate, who warns them of how their ghost stories attract spirits. While out walking, Mai sees the building that all the ghost stories surround and decides to go in. As she is about to touch a camera she found in the middle of the room, a man stops her and ends up injuring himself. Mai is then forced to work as a stand-in assistant for the man, an employee of the "male student," who was hired to study the "paranormal" events occurring at the school. Mai nicknames this "student" "Naru" for his narcissistic attitude. Naru owns a paranormal investigation company SPR and Mai eventually earns a part-time job at SPR after assisting with the first case. The more involved Mai becomes with Naru, the more she learns about herself and her feelings towards him. Along with Shibuya's assistant, Lin, the SPR also finds itself assisted by various spirit mediums and exorcists. (Source: Wikipedia)

The two books are a continuation of the Evil Spirit Series (Akuryou), but in a different setting.

The decrepit building was condemned long ago, but every time the owners try to tear it down, "accidents" start to happen-people get hurt, sometimes even killed. Mai Taniyama and her classmates have heard the rumors that the creepy old high school is haunted-possibly by ghosts from the Second World War. So one rainy day they gather at the told school to tell ghost stories, hoping to attract one of the suspected spirits. No ghosts materialize, but Mai and her friends do meet Kazuya Shibuya, the handsome young owner of Shibuya Psychic Research, who's been hired to investigate paranormal activity at the school. Also at the scene are an exorcist, a Buddhist monk, a woman who can speak with the dead, and an outspoken Shinto priestess. Surely one of them will have the talents to solve this mystery! (Source: Del Rey)