The goal was definitely to impede the other researcher's work, and I can imagine a few possible reasons for that. In descending order of probability, interpersonal conflict (in my experience, graduate students in the same lab tend to either become best friends or hate each other, with little in-between), trying to beat the other student to the punch w.r.t publication, or good ol' schizophrenic delusions that the person's work needs to be stopped (mid 20's is a pretty standard age for onset in men).
> interpersonal conflict
low probability in this case because this guy seems a repeat offender but absolutely things can get that toxic and ugly
> trying to beat the other student to the punch w.r.t publication,
this is my highest suspicion. Why is anxiety. Deep anxiety. Anxiety about failing. Anxiety about the other guy beating you. Sabotaging other guys's computer alleviates the anxiety so thusly becomes a repeat pattern. Anxiety can be quite insidious and nasty and is more pervasive in more ways than many are aware.
> good ol' schizophrenic delusions that the person's work needs to be stopped
possible but more rare
