How should my best friend react to a possible threat from her ex boyfriend?

My best friend (we’ll call her A) broke up with her boyfriend of about a year (L) a little over a month ago. L has never been what I would describe as mentally stable. Throughout most of their relationship he was depressed and suicidal. His personality always struck me as extremely negative, cynical, angry. But he has not been handling the breakup well and is starting to scare A. For a while he was just badgering her to get back together with him, but she just kept shutting him down and finally blocked him from calling her. Now one of their mutual friends (S) has just come to A to tell her things that L has been saying to S. S showed A some text messages in which L said that he wants to try and get A kicked out of college by hacking into the college’s network and changing her grades, and framing A for it. Then he said, “but, it’d probably be easier to just shoot her.”

I don’t know what to advise A to do. L is kind of a big bullshitter and makes empty threats all the time. As a side note, I’m fairly certain he wouldn’t have the skills to hack a college network. But, my policy is better safe than sorry and I have to admit that I’m pretty worried about her. She’s going back to college tomorrow and plans to talk to campus security about him just to make them aware. What else should she do? She definitely doesn’t want to do anything to make him more angry.