"Her head's smashed in, but Cooper found petechial hemorrhaging and some possible ligature marks on her neck, too, so we'll have to wait for the post for cause of death." (2.70)
Katy's murder is pretty gruesome, and even though she's twelve, the story doesn't shy away from the gory details. Perhaps it gives us more than we'd ever ask for to further illustrate how terrible this murder of a child is.
"She was killed somewhere else, probably kept for a day or so and then dumped." (2.73)
That's pretty vile. Someone not only killed Katy, but stored her somewhere, and then dumped her body like a bag of garbage. It takes a really twisted person to do that to another human.
"There were two blows to the head, both ante-mortem—before death. […] Both were struck with a hard, rough object with protrusions with no distinct edges." (5.71)
In the Woods doesn't shy away from violence or investigating the violence, such as this exchange during the autopsy of a twelve-year-old girl.
"The rape was post-mortem, and was performed using an implement of some kind." [Cooper] paused, discreetly enjoying the effect. (5.84)
Cooper, being the forensic examiner, has probably seen many more violent acts than this one, which to us, is horrifying. He's desensitized to it, though, and seems to relish shocking other people with graphic details.
[Sandra's] skirt was twisted up around her waist and there were huge rips all down her tights. (11.105)
Rob remembers this detail from Sandra's violent gang rape. The way Jonathan tells it, it almost seems quaint—holding down a girl and having sex with her. But Rob witnessed the violence of it, and recounts an image like this to illustrate how awful it was.
"Shane, only. Not that that makes it any better. I helped hold her." (13.63)
Jonathan was complicit in a gang rape when he was a teenager. Has he changed as an adult, or is this capacity for violence always a part of him?
"You know what that b**** needs, don't you?" Cathal said. (13.124)
Cathal thinks other men are like himself: violent and primal, and unable to control these urges, especially when it comes to women. If he didn't, he wouldn't so openly speak this way.
We decorated it as carefully as a stage set. Photos of Katy, alive and dead, spanning half a wall. (14.2)
Rob and Cassie use the violent contrast between life and death to manipulate interrogation suspects. It's hard not to be honest when confronted with the stark details of a violent crime.
I lunged at [Jonathan]. […] Cassie was on me already, grabbing my raised arm with both hands. "Jesus, Ryan! Stop!" (14.119)
Rob threatens Jonathan with force, but this time, he's serious—he and Cassie struggle, for real, and he ends up hurting her. Rob is unable to control his violent impulses when angry in this situation.
We heard scuffling, the crunch of twigs snapping underfoot; then a swift, vicious noise like the hiss of a cat, and something between a smack and a thump, and a sharp gasp from Cassie. (24.170)
Rosalind ends up losing her cool and attacking Cassie, scratching her face. She might prefer manipulation, but this evil teen isn't above letting her claws out, too.