RETRIBUTION
Nerds and spiritual possession. The rest writes itself.
A mousy painter tries leaping to his death off of a building (the next time I try to kill myself, remind me not to pick a method that's guaranteed to draw scores of people who cheer me on) at a spiritually inconvenient time. For you see, at the same time that some unlucky bastard across town is getting tortured to death. The painter survives, but when he sleeps, he dreams of being possessed and cruelly acting upon those responsible for themurder.
It's not too bad overall - it benefits from some nicely grisly murders, an oddball romance with a sweet hooker, and some really anti-Hollywood casting in the lead (I mean, most "mousy"people in the movies are good-looking Hollywood people playing a role. This guy looks like he should be doing my taxes.).
But it suffers from being about 25 minutes longer than it needs to be. Additionally, once the connection between the murders is revealed (as if you couldn't figure it out), one wonders why one would bother putting a stop to them.
Hoyt Axton (who I'll always remember as the gut-rupturing guy in Endangered Species - that scene inexplicably put me off ginger beef for a year) shows up as a cop looking into all the nastiness.
It's certainly miles above Mausoleum, the last possession flick I saw.