<P> Dan grew up in Tree Hill, NC and attended Tree Hill High, where he was the star of the Ravens basketball team . Towards the end of senior year, Dan got his girlfriend Karen Roe pregnant, but abandoned her to take a basketball scholarship to North Carolina . At college he met Deb Lee, who also became pregnant by him . Dan returned to Tree Hill on the night his and Karen's son Lucas was born but, on seeing Keith with Karen at the hospital, Dan left without Karen seeing him . Dan and Deb married and moved back to Tree Hill with their son Nathan . Dan tried to get joint custody of Lucas, but Karen refused and Dan gave up on trying to be part of Lucas's life . He later became a successful car salesman having set up his own business with Deb's money . Dan is a man with big dreams and expectations, especially regarding his son Nathan, but he doesn't handle it very well when they're not fulfilled . </P> <P> Dan is a controlling father to Nathan, who is now the Ravens' star player, but has nothing to do with Lucas . When Lucas joins the Ravens, Dan encourages Nathan to give his half - brother a hard time . Dan puts so much pressure on Nathan that Nathan takes drugs to enhance his basketball performance, leading to him collapsing on the court . When Deb finds out, she asks Dan for a divorce . When Dan's parents come to town for Dan's birthday, it is revealed that Dan's father Royal put similar pressure on Dan and that Dan faked the extent of an injury he suffered in college in order to give up basketball . Dan also has an uneasy relationship with Keith, due to Keith's continuing friendship with Karen . When Keith crashes the car he is driving with Lucas inside, Dan pulls Lucas from the car and saves his life, leading to a temporary truce with Karen . Keith is left in financial difficulty due to Lucas's medical bills and Dan offers to buy Keith's garage from him while Keith continues to run it . However, it soon becomes clear that Dan will be running the garage in his own way and Keith quits . After being rejected by Karen, Keith turns to Deb for comfort and they have a one - night stand . On walking in on them in bed together, Dan tells Keith that he is no longer his brother . Dan is about to sign his divorce papers to Deb when he suffers a heart attack . When Deb finds Dan on the floor, Dan tells her "you'd better hope I die ." </P> <P> After his heart attack, Dan claims to be a changed person and tries to get closer to Lucas . Dan and Deb are united in their disapproval of Nathan's marriage to Haley . Dan claims to have forgiven Deb and Keith for their fling and a guilty Deb allows Dan to live with her while he recovers . It becomes clear that the new Dan is an act when he lies to Deb after being given a clean bill of health and it is revealed that Keith's new girlfriend Jules was actually hired by Dan to seduce his brother . On discovering that he has the same heart condition as Dan, Lucas agrees to move in with Dan on the conditions that Dan pays for Lucas's medication and keeps this from Karen, and also that Dan leaves Keith and "Jules" alone . Dan keeps his promises but Karen discovers the truth about Jules and threatens to tell Keith, leading to Jules leaving Keith at the altar . Dan is delighted at this result and, after knocking down the groom on the wedding cake, looks at Deb saying "one down, one to go". On discovering what Dan did, Keith confronts Dan at the dealership and attacks him . Before leaving town, Keith tells Dan that he has nothing left to lose, but Dan does . When Nathan and Haley's marriage is in trouble, Dan is quick to pounce, and gets Nathan to sign annulment papers and move back in with him and Deb . However, Deb wants Dan out of their lives for good, especially after learning that Dan told Nathan that it is his fault that Deb is now addicted to pills . Lucas continues to live with Dan in order to bring down his father once and for all . He finds cash and an incriminating ledger in the attic of the dealership and discovers that Dan has been making money illegally by changing the amounts on bills and pocketing the extra cash . However, Dan has made Deb the co-owner of the dealership, meaning that she would be incriminated too . Dan then reveals he left the cash and ledger for Lucas to find as a test of Lucas's loyalty, which Lucas failed, and so Dan severs all ties to Lucas, even cutting off his son's heart medication . Dan also sabotages Karen's relationship with her business lecturer Andy by walking into one of Andy's classes and telling everyone that Andy is sleeping with Karen, which leads to Andy losing his job . Dan then tries to have Andy deported back to New Zealand . When Karen angrily confronts Dan at the dealership, Dan grabs her and forcefully kisses her, saying "isn't that was this is really about?" At the end of the season Dan falls unconscious after drinking a poisoned bottle of whisky that was left for him with a note saying "for everything you've done". The dealership is then set on fire with Dan inside . </P> <P> 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 . </P>

When does dan get arrested for killing keith