Fruitfly Problem

So I have no fruit around. I got rid of it all the other day when we had a few of these flying around. Now three days later there is still three or four flying around. I have studies about these little guys on the internet and discovered they can live in the drains-- which is where I am guessing their leader is. I need to find him and exterminate him/ her in order to solve the problem. Anyway, anyone ever had this problem before and if so how did you take care of it? I am going INSANE!