Hello my mystery-writing friends.

I'm finding myself a bit stuck in the mud. I write fantasy mostly, and while there can be mysteries in those stories, the stories aren't mysteries. But I have this idea for a novel that I really like, concept-wise, and it ends up being a bit of a murder mystery. But, it turns out, I don't really know how to go about writing those.

A bit of background on the story. My main character can use magic that allows her to communicate with the reapers that come to collect souls when people die. One of the uses is that she consults with the police to help solve murders. Some people have mysteriously died, so she's working on that. Who the dead people are doesn't really matter for purposes of the plot. What matters is who killed them, why, and how. I mostly have all of that worked out.

What I don't have worked out is how to go about actually plotting the book. I've gotten about 16k words in, which has introduced some of the pieces. But now I've stalled. I don't know how to go about slowly revealing evidence, how to figure out which pieces to reveal first, etc. So my question is how you all figure that out. How do you construct your mystery? What methods for getting the plot in order have worked for you? I'm really excited about the potential of this story, but I just don't know how to pull off.

Thanks!