suicidal help contacts?

[JUST HOPE☺○♥♦♣♠◘•☻♥•.¸.•*¨*]

i've seen someone on twitter send multiple tweets about the actions theyre going to do to kill themself. She's tweeted during and after the stuff shes done too. She hasnt tweeted in a while, and its really concerning me. i dont know if its a follow hoax or not, but i have to take precautions.
is their a site or number i can report this to so that they can investigate and find out how it happened, or atleast get to her family to see her last messages. just like the police go and solve some cyberbullying, im looking for one that would help with suicide. i dont know if kids help phone would do that, since they may not have the power to look deeper into it. should i contact the twitter people?
i dont even know im so confused.
and dont tell me not to do anything because thats not going to help anyone.

[Teenage]

http://www.suicidepreventionlifeline.org/


Please, suicide is never the answer

[Helpful Guy]

find out the non emergency number for the police in your town. when I answer, explained the situation about the girl on Twitter.