how to handle vague death threats online?

my partner has a coworker that’s constantly talking and posting about seriously hurting/offing people in their workplace, including my partner, without mentioning their names, just significant things that they do in the office to identify who their talking about. my partner is scared and worried that said person might actually hurt people. does anyone have any advice on what to do in this situation?

i’ve never really met anyone like this before so i can’t give my partner proper advice. i usually resort to confrontation, but my partner is scared of things escalating. in my perspective, her coworker is being childish and edgy online, but i might be wrong as well.

to add more context, my partner was pretty close with this coworker before. but recently, she tried to give advice on how to manage their emotions and try not to think about hurting others. but now, she’s also posting about my partner.

i’m just lost and can’t bare to see my partner always feeling anxious being at work.

(ps. apologies about the poor grammar, english is not my first language)