Should I Confront?

Okay TSR, time to pick your brains!


(Long ass story warning)
So my friends, lets call them Mary and Hannah, have had a rocky history, they've been friends for 2 years before they came to uni. When Mary became friends with another girl called Shirley, Hannah felt like she had been pushed aside.

Fast forward to a few months of slightly rocky friendship and Mary contacted Hannah letting her know she had a revision session to go to, Hannah literally flipped the F out and started accusing Mary of saying she was stupid and so a massive argument ensued resulting in Hannah blocking Mary after accusing her of attempting suicide for attention and saying she isn't really depressed.

(Side note, I've read the whole conversation, no screenshots or anything and Hannah literally went nuts!)

Hannah is now telling people that if Mary was to get with a guy that she would go to the police and say that she was raped. (Mary wouldn't, to clarify) As well as saying she should just die which of course isn't helpful when Mary is already seriously depressed.

Am I within my rights to shove this little troll in the bin where she belongs or at least confront her and call her out?