my mac was stolen, could it have gotten erased before i activated the FMM feature?

Yesterday my suitcase with my mac in it was stolen on a train from Kiel to Hamburg. (I am in Germany right now) I only noticed it was missing shortly before we got to Hamburg. Likely though the thief left the train at one of the stops in between Kiel and Hamburg.

I activated the find my mac feature when I finally got home after I went to the lost and found place at the main train station in Hamburg. I also remotely locked it and activated the sound thing.

Since then I keep getting the same message, that the computer is not online. I am wondering if whoever took it was able to open and erase the contents and operating system on it before i was able to activate the feature. Would that disable the FFM feature, or would it still be able to locate my computer? (It's a mac book pro)