There's a difference between 'pranking' someone and persistent, constant abuse, and while it was a waste of tax money, it's at least hopefully made him at least think about not doing it any more, god knows there's enough borderline retarded douchebags queueing up to take his place.
Call me in favour of a police state, but I'd like there to be some kind of law where constant, relentless and extreme verbal abuse gets to the point where it's illegal. Sexual and racial abuse shouldn't be the only stuff protected, hell, I thought it was illegal to abuse someone on the basis of their sexuality, and I wouldn't want someone arrested for letting slip the occasional 'fag', but if you're constantly harrassing someone online, there ought to be some comeback legally. Not everyone is strong enough to handle abuse, and I thought we'd evolved as a society past the point where we just ignore the weaker members.