Is there a way to find out who...

Same answer. No not really. You can look at history logs and cookies (if they were not cleaned up) to try to see where someone has been surfing. But this will not tell you if you got infected from a particular website. You can look at file on the PC, what is being installed, and downloaded, but this still does not tell you where the infection came from. It may give you some ideas, but not necessarily any proof. The only thing you can be sure of is the infection itself and that is only when it is found. Some infections do a great job of hiding.