Horn disconnected from car break-in
 

I own a 2011 LT with a stock alarm and a few days ago my home security camera caught a suspect breaking-in and steal my belongings. I watched him going under the front bumper and driver side door and was able to gain soundless entry.
This is the 2nd time this happened where my horn is disconnected from this act. I was wondering if anyone knew what I could do to prevent this from happening again. I'm open to all suggestions (i.e. car alarms, wire barriers etc.) Thank you.

Sorry in reading of this action.
Move horn to inside of engine compartment?

Thank you for the suggestion! I didn't know you could do this too.