I need advice about teenage girl drama, i don't know what to do. Could anyone help the situation?

Alright, a couple of days ago i over heard my really good friends, Emma and Claire, talking about my other really good friend, Abby's, back about how Emma's ex-boyfriend is dating Abby and how now she hates abby and how she wants her to die and i thought that this is a very serious situation because anyone that wants someone do die needs to talk to someone. also i know for sure that Claire is like best friends with Abby and it made feel like she's twofaced or something. so then yesterday i went up to Abby and told her what claire and emma said about her behind her back and so we went to our teacher that we both trust and she said that she'll talk to them. so then after leaving her room, relieved that no one will find out that i told Abby i go along my day, then in last period i took out my phone to see what time it was and it said i had a message so i read it and i was completely shocked because it was emma and she was just cussing my out and said that im starting drama, me! and said that i better back off, and now i dont know what to do because abby islike my best friend and i care about how she feels but what do i do about claire and emma? because i still dont know how they found out.