Warren first appears on March 17, 2010, when Lucky Spencer questions him in order to establish a timeline of the night of Kristina Davis's first attack. Being a lawyer, Warren is resistant and dismissive, but eventually agrees. After a bit of questioning, Mac comes to them and says Mayor Floyd feels the Bauers have shown good faith by coming in and their interview is over. The Bauers are sympathetic to Kristina, but feel since her father is a mob boss, anyone could have attacked her.
Warren reappears on April 2, where he speaks with Jasper "Jax" Jacks and Skye Quartermaine, and subsequently speaks to Kiefer about Lucky and Dante's ongoing investigation into Kristina's attack. Warren bluntly states that he thinks Kiefer never should have gotten involved with Kristina and encourages his son to talk to her. Lucky and Dante, having already deduced that Kiefer was the one who attacked Kristina, later question Warren and his wife, Melinda, over the attack, but they are not much help.
On April 6, Warren meets with Jax on business, and discovers from Olivia Falconeri that Kiefer has been hit by a car and brought to the hospital. Upon arriving, Melinda and Warren find Lucky questioning Kiefer. Warren pulls Lucky out of the room and criticizes him for trying to question Kiefer in his condition, and Lucky informs him that Kristina has been attacked again and that she has finally named Kiefer as her assailant both times. Kiefer dies from his injuries, and Warren immediately gives a press conference, offering a reward for information on their son's killer.
Warren discovers from Mac Scorpio that Alexis was the one who hit Kiefer and that it was an accident. Outraged, Warren convinces himself that Alexis did it on purpose and swears revenge on both Alexis and Kristina. Later, Warren harasses an already-overwrought Kristina until Alexis and Jax arrive and force him out of the room.
Subsequently, Warren posts a memorial page online, painting Kiefer as an ideal person and student and also adding a video, where he gives his own scenario; he states that Alexis deliberately ran down Kiefer, and also claims that it was Ethan Lovett (whom Kristina had originally accused of beating her to protect Kiefer from her father's wrath) who attacked Kristina all along, and that Alexis and Sonny had convinced Kristina to lie and tell everyone that Kiefer was the one who attacked her because of their friendship with Luke Spencer, Ethan's father. He later confronts Kristina in her own home and, in an attempt to get her to change her statement, fuels her grief and guilt by repeatedly reminding her that Kiefer loved her. When Alexis arrives home, she criticizes Warren for his actions, and his demeanor immediately changes; Warren calls Kristina a pathological liar and Alexis a child killer, and vows that he will make Alexis pay for what she did to Kiefer.
Warren subsequently confronts Mac at the police station and demands to know why Alexis is still running around free. When Alexis arrives, Warren demands to know why she did not stop and refuses to believe her story. Alexis calmly asks Warren to stop making everyone miserable, but Warren stops her and promises to send her to prison. Alexis' oldest daughter, Sam McCall, arrives to see Alexis arguing with Warren. Warren furiously continues to deny Kiefer's abuse of Kristina, and angrily declares that he will not stop until the whole world knows that Alexis is a murderer and that Kristina is nothing but a "promiscuous little tramp" who deserved to get beat up, at which point Sam loses her temper and punches him in the face.
Lucky is roped into the confrontation as Warren and Sam exchanged heated words. Warren points out the evidence they had originally found against Ethan and accuses both Lucky and the Davis women of framing Kiefer. Dismissing any and all evidence against Kiefer, Warren leaves, but not before telling Alexis that she belongs in prison and he will see to it personally that she is sent there.
On May 13, Alexis goes to court for Kiefer's hit-and-run. Much to Warren's outrage, the jury rules in Alexis' favor, and she gets off with a suspended sentence and community service. Warren subsequently files a wrongful death suit, vowing to take Alexis for every penny she has. On May 18, Nikolas Cassadine confronts Warren and attempts to get him to back down. Despite Nik's best efforts, Warren refuses to drop the case.
Proceeding these events, however, Warren begins to unravel and begins to call Claire Walsh's office twice a day for a month and using whatever tactic he can think of to try and pressure her into reopening Kristina's abuse investigation, to no avail. Warren later approaches Kristina, Alexis, Molly, and Sonny at the country club to inform Alexis that he is going through with the civil suit and that her court date is coming up soon. Warren continues to heckle Kristina and Alexis, and just as he begins to get really aggressive, Sonny gets in his face and warns him to back off. Asserting that abusers learn their habits from others, Sonny openly accuses Warren of having abused Kiefer himself. Though Warren denies it, it is obvious from the look on his face that Sonny is correct. Nonetheless, Warren leaves without causing any more trouble, vowing that Kiefer will get justice.
Subsequently, on July 21, Warren arrives at General Hospital and demands Kristina's medical records from Epiphany Johnson, but she refuses to give them to him. Just as Warren begins to criticize Epiphany for helping to protect Sonny's "little lying slut of a daughter", Olivia enters and calls him out. After the argument, Warren threatens to sue Epiphany and the hospital for obstruction of justice unless he gets Kristina's medical records by the end of the day. After he leaves the room, Epiphany throws his court order in the trash.
Coincidentally, Kristina is in the hospital with a sprained ankle, and Warren corners her in a room shortly after the hospital is locked down due to Franco kidnapping the newborn Aiden Cassadine. Warren demands that Kristina sign a release for her medical records, but Kristina openly refuses and berates him for abusing Kiefer. Warren snaps and attempts to slap Kristina, but just as he is about to do so, Michael, having heard Warren screaming at Kristina, rushes to Kristina's rescue.
In the ensuing skirmish, Michael quickly overpowers Warren and brutally strangles him to near-death, but is stopped from doing so by Lucky, Ethan, Maya, Mac, and Steve. Warren claims that the attack was unprovoked and demands that Lucky arrest Michael, but Lucky and Mac immediately deduce what really happened and cleverly make it impossible for Warren to press charges against Michael. Subsequently, Warren suffers a psychotic breakdown and induces a shootout, critically wounding Mac and Ethan before turning his attention to Michael and Kristina. Before he can pull the trigger, however, Mac garners enough strength to shoot him in the back. Warren quickly succumbs to his wounds, but not before telling Kristina, "This is all your fault."
Abused his son, Kiefer [pre-2009-2010; revealed on Jul 19, 2010]