About how long was it.... and where in the world is this?  One thing that's supposed to work well, and isn't hazardous, would be Diatomaceous Earth... not the kind that's sold for swimming pools, though... from what I gather, that has been "fired", and loses it's effectiveness, because of it. The trouble is, it takes a while... nonpoisonous, though. If it is small, it may be what we used to call "Pill Bugs" when I was a kid... nudge it, and it'll roll up into a ball... harmless to humans and pets... those are usually a kind of bluish grey, and less than a half-inch long. Lou.

"..... and that was when things got interestiing."