Big ups to Spain
"Our final aim is to delete the data according to our legal obligations"
I would have thought that Google's legal obligation in this case is to keep the data, since it's evidence. They can be ordered to delete the data once they're found guilty. The only Fail here is that probably the person responsible will get away scot-free... the result would be a fine for Google and maybe a personal prosecution for some low-level company scapegoat.
This is really a weak point in company law that companies abuse to hell and back - they have all the advantages of being a legal person, without quite a few of the disadvantages. eg I would probably go to jail for driving around and collecting people's data. You can't send a company to jail, and even though in theory company directors can be responsible for some company actions, in practice it's always easy to say that some rogue employee(s) somewhere down the line did it all.