Rat Killin

I spent the weekend trying to kill the little bastard that is getting into my house. After checking the attic and the crawlspace, I confirmed that A. It's not a squirrel in the attic, and B. whether it's a mouse or rat, it's getting into the house from the crawl space.
I put a trap in the garage, where there's a heating duct that goes into the crawlspace, one in the attic, and one in the crawlspace. The next day, I checked them and the one in the crawlspace had tripped. All the peanut butter was gone, but there was no victim. The trap was kind of sensitive, so it may have just triggered on it's own and then the invader came by for a meal. At this rate, all the peanut butter will eventually give him a heart attack.
I know rats are pretty smart, but I'm hoping not smart enough to know to stay away from the traps, or worse, to figure out how to trip them without getting caught.
If this fails, I'll have to get the glue traps. With my luck, the little bastard just escaped from NIMH.

UPDATE: Yep, I have super rats. I found that the trap in the attic and the one in the crawl space had been triggered and moved about three feet. There was still peanut butter in them, leading me to think that Nicodemus got hit, but there was no body.
I'm going to need a bigger trap, or at least add some spikes to these.

UPDATE: Technical tip. JB Weld will not bond finishing nails to a rat trap. I think it's the bronze of the trap wire. It just doesn't stick to it.