Horror/Ghost short story. Siblings claim they can preform séances, but fake them for money.

[Francesca]

I read this book in either 2017 or 2018, and it looked fairly new. It was very short, only around 60 pages. The cover was white with a shadowy silhouette figure.
A brother and sister would fake séances and claim to talk to the dead as a scam for money. The brother was sceptical and wanted to back out.
A murder was committed and the sister started to feel the presence of the victim and other spirits.
Pleas help, thank you!

[Kris]

Shan, is this book for teens or adults? How old are the siblings?

What is the story's time period and location (country, region, well-known city, small town)?