So, it looks like they arrested a couple young men who were suspected of creating both the Mytob and Zotob worms: 

It’s hard to believe that an 18-yr old (Farid Essebar, a Moroccan national born in Russia) and a 21-yr old (Atilla Ekici, a Turkish resident) could be responsible for such wide-spread destruction. My son is nine, and the only kind of worms he’s interested in are the type you use to bait your hook when you go fishing (yes, that’s fishing with an “f”).