I think you're right to be concerned.
In our area, we had a couple suicides last year and the media mercifully didn't carry the stories much, because it causes other girls to copycat.
It's like when a girl in high school gets pregnant lots of other girls decide to do that too.
Since she's mentioned this several times, I really think this bears looking at further to protect her. Can you get the name of a good children's therapist from your school?
It could be delayed grief ..and its good she is talking and crying..I personally don't think any child should watch TV news there is much on there with these riots ,much is very graphic.So have the news on in a room where she doesn't see it ..many times I have heard about children who have nightmares, don't sleep, and are very upset, turns out older family members forget about youngsters in the room and have all kinds of scary movies on...look at this present time ..Dracula, Zombies, some really crazy stuff that actually scares me ...Hope she feels better soon I know you are concerned it will get better but make sure she really isnt privy to the stuff on TV and on a Computer.
The best thing you can do is remain calm and be there to listen. It's really good that she trusts you enough to tell you how she feels. When anyone loses someone close to them it's normal to want to join them, but it's not a good attitude to endorse. I took a few classes in college from a suicidologist named Ralph Rickgarn (RIP). He told us that you should take it very seriously whenever anyone says they are thinking about suicide. Immediately find her a therapist. She needs a professional to help her through this. Even if you don't think she is truly serious, you should still address it. No 10 year should feel this way! He wrote a book on this called "Perspectives on College Student Suicide." Even though it's aimed at college students, there is good info in there for everyone. If she does try anything, take her to the hospital right away for psychiatric care. She sounds like such a sweetie! Good luck.