Separated? - Why didn't they tell them?

Leia Asher and Camila Asher are twins, fraternal twins. They were separated at birth. When Leia starts Middle School, Camila ends up attending the same one. They began to develop the best friendship ever, and both consider each other best friends. But then, Leia asks her mother Gina, if her Camila could come over that weekend. Gina says yes, but ask her parents first. Camila's dad (Leia's dad) said yes also, and that weekend when Camila came over began something horrible.