My sister has threatened to kill me for her student loan debt?

I cosigned a student loan for my sister to go to college. After finishing college she managed to land a high paying job at a major league news station . She made great money for 10 years but paid NOTHING to her student loans. She partied, bought expensive things, and bragged about her amazing vacations. 

can you imagine that? 

After 10 years of living the celebrity life, the station fired her. Now she's a poor pitiful b*** like the rest of us and can't afford anything. Since then, she finally opened a student loan letter for the first time and BOOM ! She immediately knew what to do! 

She threw a brick through my car window and left a note demanding for me to make a payment... 

O___o

During the years she was partying with her newscaster buddies I worked a humble job at a local magazine and drove uber on my days off.I saved my money and invested in a 401k. My 401k and savings are enough to pay for her loans, but I don't see why I should pay for her loans.

My sister has sent me several text messages, demanding money and blaming me for everything. she says I ruined her life and that she wants "revenge" . I have no idea why she blames me for her student loan debt when all i've done is try to help her

my sister is homeless now and I feel like no matter what I say to her it will always be my fault according to her. 

what should i do?