Scream. (Story I made)

Delaney and her friends are having a normal life but Delaney has been having a tough time with her mother's loss. Her friend Joelynn and Kat are helping her with it. Delaney goes to middle school and has Kat in her class, Kat is her best friend and Delaney thinks she's funny. Delaney was at her house and a stranger calls and talks about horror movies that they like, Delaney thinks it is her best friend Joelynn messing around with her until the stranger admits and says they are not Joelynn and they ask "Do you want to die Delaney? your mother sure didn't." Delaney survives an attack by a killer. Delaney and her friends find out that a murder has happend at a students house. Later one day Delaney and her friends want to cause some trouble by staying at the school after hours to see what it's like, but they soon realize one by one...they slowly start going missing. They hear screams in the hallways and try and see what it is but everytime they are close to finding out who the killer is but everytime they disappear. it's up to Delaney and her friends to find out who this mysterious killer is that is making her friends go missing.