Whenever Courtney was drunk, she would seem to take out her messiness on Lily. In the past she has thrown a drink in her face, and got into a heated argument with her. 

A week before the murder, Courtney left an extremely drunk and rude voicemail to Lily. In it, Courtney called her attention seeking, said that none of her friends actually liked her, and slut shamed her. Courtney claimed to have no recollection of leaving this voicemail, as she was too drunk to rememeber anything she did that night.