Car Alarms: what would trigger the alarm, alarmtek, dash area

Question
I have an '03 Mach 1, vehicle is never locked but keys are not in the ignition.  Alarm has never gone off until last night - what would have triggered that?

Answer
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?
Or,
is it: flashing parking lights,
an LED in the dash area, and a siren
going off?

Let me know more on this to better
advise you on a course of action
to take, to help you to fix this
situation you're in quickly.

Best Regards,

Robert Martin
CEO/ALARMTEK
CARALARMMAN.com