I think its safe to say the "friend" he was referring to, was Angus.
OMG! He's a genius! He's been stalking her since college and even managed to get an apartment with her so that he can stalk her up close! This explains everything! Only, now she's starting to socialize and he can't have that, so he's making his move. WHY DIDN"T I SEE IT BEFORE??!!!
Because you aren't so paranoid that you assume that everyone is not only lying, but telling and living a huge lie just to conceal their evil plans?
he says "we've known each other since college" but she seems surprised that he even knew who she was in college. Something does not compute in my head.
Apparently your college experience is incomplete, since it does not include the "mystery guy" (or girl; less common, from my experience, but I see no reason for her not to exist). Everyone you know has seen him, no one has seen him actually talking to anybody, and no one knows what he does, although at least one person of your circle is certain he was in this hundred-plus student class they were in, too. Sometimes you actually get to meet this person and discover he's cool, interesting, brilliant, obsessed, creepy, strange, non-communicative, lonely, self-absorbed, distrustful, or personally disturbs you—take about three from the list, and you might add has some odd odor. I recall about three guys like this from college (including grad school). Two I met, and one just faded away about mid-semester. Legend had it 'they' came for him (although no one ever properly established who 'they' were.)
Marigus, definitely.
Because not enough words rhyme with asparagus.
And Angold sounds like something from a Wagnerian opera...
Stop that.