The oak bark beetle is about 1/8 inch long, dark brown, and about 1 millimeter in diameter. The adult female lays her eggs on dead or dying oak. It was probably brought into the home with firewood. The larva burrow in and feed, usually in the cambium region of the wood. Adults normally emerge in the spring. There is usually one generation per year, so you should have no continuing problem once you get the current emergence cleaned up. In the meantime, get the firewood out of the house. If there was no oak firewood, then you have some other item of oak that was infected, and you need to remove it from the house, or if it is small enough, put it in a plastic bag and put it in the freezer for a week or two. This will kill any larva or pupa that are left inside.
Cooperative Extension Ventura County