1. If you werent at the scene you are not in trouble
2. Suicide does not equal murder! Unless you were the bully.. you may not go to jail, but keep in mind that your immaturity caused these actions and it is your duty to apologize and learn from your mistakes.
3. If someone you know is threatening to commit suicide, call their parents, relatives, or even cops. Don't just turn a blind eye.
4. It all depends on the severity.