Active Alarm Can A Burglar Disable A Car Alarm System?

Can a burglar disable a car alarm system? - active alarm

I have in my car this morning and had all my belongings thrown on the front seat, interior lighting, etc. As my car, I pressed the button on the door and close the alarm, but still does not alarm. For info: Like most cars, sirens and fire comes as a rule, if the alarm is activated. Neither will happen if I am now on the button.
* I drive a Nissan Altima 2002
Thanks for any help.