Car Alarms: bmw 5 series, faulty alarm system, bmw 5 series

Question
I would like some advice as to if my car alarm could be going off on its own or if some one may be messing with it. due to construction my car is being parked road side. the alarm has never been corky in the past. it went off  last sat. night and then last night( a week later). i have not found anyone with the car. I just had a new computer abs controler, and all that goes with that, put in the car last week. so it happend once before and once after. i dont think that is to blame. I also just had a diegnostic done on the car a month ago. would a faulty alarm system show up on that?  How would you persue this?

Answer
Please be more descriptive if possible.

"GOING OFF?"

I need to determine whether it's a factory alarm
issue or, if it's an aftermarket system you are
dealing with.

Is it: Headlights flashing, car horn honking
and a worded SECURITY" light in the dash flashing?
(doubtfull since none of the notes show this
car as having a factory alarm system)=FACTORY

Or,

is it: flashing parking lights,
an LED in the dash area, and a siren
going off?= AFTER MARKET

Let me know more on this to better
advise you on a course of action
to take.

Best Regards,

Robert Martin
CEO/ALARMTEK
CARALARMMAN.com