Car Alarms: Alarm, shock sensor, vantage point

Question
This weekend I had my Mercedes broken into and stereo taken. I have an alarm which is very loud, it did not go off? My car was parked right outside my bedroom window so I would of heard it go off. Do you know why it didn't go off? Is there away for someone to disarm the alarm before breaking in? It is the strangest thing, my alarm is super loud. I hope you can help me answer my question or lead me in the right direction. It has really be bothering me. Thank you

Answer
Only thing I can think of is that it simply was not
armed at the time, or it was not installed
correctly. Hard to say from my vantage point really.

Have the installer look over your security system to explain it.

If installed right, the doors opening would
have set it off. Shock sensor would back that up.

Have it looked at.

ALARMTEK