Kiefer helped Kristina cover up the incident that killed her unborn baby brother. She always sided with him because Kristina feared his mental and verbal abuse. When Kristina began developing feelings for Ethan Lovett (then Nathan Parsons), Kiefer's jealousy took over and he physically beat her up. Prior to that, Ethan and Kristina had an argument, and when he went to apologize to her, Ethan found Kristina badly beaten and rushed her to the hospital. Since Kristina was afraid that Sonny and his enforcer, Jason Morgan (Steve Burton), would kill Kiefer if they knew the truth, she blamed Ethan for the assault.
He was arrested for the attack, but she later convinced Alexis to drop the charges. Because of that, Kiefer beat her up again. However, Alexis saw him leave their house and found a battered Kristina out cold. She rushed her daughter to the hospital, and in her haste, Alexis accidentally ran over Kiefer and she didn't stop. Kiefer died from his injuries, and Alexis kept quiet about what'd happened.
Ethan was arrested for being the hit-and-run driver, but Jason knew Ethan didn't harm Kristina, and he convinced the police to look into the matter. After a while, the guilt got to Alexis, and she admitted to Kristina that she was the one who killed Kiefer. Kristina also ended up telling the authorities that it was Kiefer who beat her, not Ethan, and the charges against him were dropped on that basis too.
