Witch Elm

I read a book a few weeks ago about unsolved murders, and it mentioned an interesting case about a woman's body that was found in a wych elm. At first police thought she had gotten in the hollow of the tree to keep warm one night and got stuck, but later they discovered fabric in her throat, indicating someone killed her. I was really curious about it, but I couldn't find any other books related to the crime. I did come up with this fiction title by Tana French, which was inspired by the case. It was really good and took a lot of twists I wasn't expecting.
Toby admits he's had a lucky life. He dodges a major bullet at work that takes down a co-worker, but then his apartment is broken into one night and the burglars beat him nearly to death. Toby goes to stay with his Uncle Hugo at his house, known as the Ivy House. Uncle Hugo has cancer and doesn't have long to live, so Toby is keeping an eye on him while he recovers. Toby's girlfriend, Melissa, also comes to stay at Ivy House. Things are going quite well for a little while, until Toby's cousin's kids find a skull in the old wych elm in the backyard. I can't say too much else without spoiling it, but she did a great job with not red herrings. I honestly didn't know who I could trust.