Katelyn's scaring me.

This is what she posted on her tumblr:
"This is the second time in a week that he has threatened to kill me.
My left arm is probably broken.

I have never been so afraid in my entire life.
Apr 30, 2011 6:15 pm"

and then later:
"there are fingers branded into my left arm.

jesus christ.

get me out of here.

now.
Apr 30, 2011 6:51 pm"

now here's the question? do i tell my mom? do i say anything? if i do, Katelyn might be furious at me. it might be nothing. like that time when I was talking to Colin online and he was acting like he was going to commit suicide, but he was really just kidding and messing with me, but it really messed with me. i was young then and i hadn't heard much about suicide, but for some reason i thought that by talking to me he would change his mind. i was stupid. but i still remember it. it scared me. and now this is scaring me. Isn't this something you're supposed to tell someone about, but what if it's not what it seems and i mess things up by telling someone. Well, right now there is nothing I can do about it, because my parents are at a party, Maeve's at the barn, and Maura and I are going to the variety show. When the show's done, I'll talk to Abby, see if Katelyn posted anything else, and then decide what to do.