Delilah's father is the greatest man she knows. So when he commits suicide she's thrown into a tailspin.
She can't eat. She can't sleep. Her bubbly personality becomes ascorbic and mean. She burns her clothes and wears all black. All she wants is to be left alone.
The thought of her father's suicide consumes her. It eats away at her.
On top of it all, his life insurance policy won't pay out for a suicide so there is no money coming into the house.
So when the foreclosure notices come it sets her into action to prove what she's known all along: that his death was a murder.