Help finding book for boyfriend’s mom for Christmas!

Hi! Looking for book suggestions for my boyfriend’s mom for Christmas. She loves Freida McFadden but has read a lot of them so I’m hesitant to get her more in case she’s already read it. She also liked the Silent Patient by Alex Michaelides.

She obviously likes mysteries! I’m more into Romantasy so I’m a little out of my element on this one.

Any recommendations appreciated!!