Were there any demon possessions mentioned in the old testament?

How does it matter whether demons are mentioned in any testament or not? As long as we have so many demons around us in this world, there won't be really any peace. Think of it, in the recent past we had Hitler demon, Mussolini demon, Stalin demon..... Now we have many in Afghanistan - Pakistan region commandeered by a master demon and there are millions of demons around us in our work place, near homes, in the market ...! So, why are searching for them in old testament?