Due to the very nature of Botnet attacks, there is no way to trace the owner, unless some serious time and effort are expended.
You would have to:
1> find the correct bot swarm's channel (out of very many) on one of many IRC networks
2> wait around for the owner to pop in, and find out where he is logging in from
3> pray that information is useful ... 80% chance it's worthless, since the owner could be anyone or could be disguising his access IP address.
The only fruitful way to find out who is doing this is if someone squeals ... hang out on one of many IRC channels used by this type of person and wait for someone to brag. That could take months of work.