My son is a biter

So this morning when I went to drop Harrison off at day care, I was told that he bit Darby yesterday on the face and that Darby had bruises. I couldn't believe it. I was so upset and mortified. I had hoped that Harrison wouldn't do this but he has and now I really want to figure out a way to stop this behavior. I of course immediately went to the internet to read up on biting toddlers and all of them said things I already knew but it also required someone to watch him, or shadow, him to see what instigates the behavior and right before he is about to bite, stop it and do it consistently. Well, I don't think that Carol has the time to do this with Harrison. I just hope this isn't a regular behavior and some thing that we can control with Time outs.