Give a stream of consciousness and then the final answer. Dan survives the fire, but the dealership is destroyed. Dan at first thinks it was Lucas who tried to kill him when he remembers seeing him in the fire, but it is revealed that Lucas saved him. Wanting access to the fire investigation, Dan runs for mayor of Tree Hill. His family-based campaign includes having Deb pretend to love him in exchange for a final divorce. This ploy works and Dan is elected mayor. As mayor, Dan gains access to CCTV showing Keith buying the whisky used to drug Dan, and when Keith returns to town Dan has him arrested on suspicion of his attempted murder. Although the police release Keith due to lack of evidence, Dan still believes that Keith was the perpetrator, and things become worse when Keith announces that he is going to marry Karen and adopt Lucas. One day at Tree Hill High, Jimmy Edwards takes a gun to school and fires it, causing a lock down. Keith persuades Dan as mayor to let him go into the school to talk to Jimmy, but Jimmy commits suicide by shooting himself in front of Keith. Dan then gets into the school, picks up the gun and shoots Keith, killing him. Jimmy gets the blame for Keith's death as it is assumed that he shot Keith before turning the gun on himself. Dan convinces himself that Keith deserved what he got as he started the war with Dan. Nevertheless, Dan becomes haunted, seeing visions of Keith as a child everywhere, and this has a profound effect on him. Realizing he has to change his ways he tries to get closer to Nathan, telling his son that he is proud of him and that he loves him. Haley then gives Dan a second chance by inviting him to her and Nathan's second wedding. At the ceremony Deb tells Dan that it was her, not Keith, who tried to kill him in the fire. Dan goes to Keith's grave and breaks down. Dan then apologizes to Karen for how he treated her and Lucas and she reveals that she is pregnant with Keith's child. Dan takes her in his arms promising to be there for her this time. He then goes home and discovers that someone has written "MURDERER" on his wall.

Based on this passage, one tree hill who tried to kill dan in the fire?
To answer the question, consider the following: At the ceremony Deb tells Dan that it was her, not Keith, who tried to kill him in the fire.
So, the final answer is Deb.