Car Alarms: acura el 99, dash area, factory security

Question
hi i have an acura el 99 with a factory alarm or factory security or whatever.
whenever i lock my car and leave the alarm randomly goes off for no reason.
why does it do 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.