ground beetles in general are hunters and may take raw meat if it happens to stumble upon it and TASTES it, just like mantids and most other carnivores in nature. most ground beetles prefer soft-bodied prey, e.g. caterpillars, but nonetheless generally have a mixed diet of all sorts of invertebrates and sometimes small amounts of vegetable matter. i suspect that ground beetle preferences also vary by species, but i do know that certain specific specifies are specialized hunters of very specific kind of prey, e.g. snails, toxic millipedes, etc. in other words, if you don't have pics or know what species yours is, you'll have to resort to trial and error. if your beetle is also stressed out, it may not feed too, so give it plenty of hiding places and a large surface area to roam about and give it time to settle in. also know that most ground beetles (except tiger beetles) are nocturnal.
another thing: are you SURE this is a ground beetle? that genus is often mistaken for other kinds of beetles, e.g. female stag beetles, bessbugs, certain bark beetles, etc.