Car Alarms: my car alarm goes off at the same time each night, nearby supermarket, mazda dealer

Question
I have recently bought a nearly new Mazda6. We got it home the first night and at 12.40am the alarm went off. Couldn't find any evidence of a break-in. The following night it went off at exactly the same time! To make sure it wasn't a coincidence, we left it active for the third night and it happened again at the same time. As we were already up the next night, we took it away from our driveway and parked it a nearby supermarket and waited for it to go off- and it didn't. Last night, back on our driveway it went off again at 12.50am. We and the Mazda dealer we bought it off are completely baffled- obviously something in the vicinity of our house is setting it off- any ideas?

Answer
It's obviously seeing either an open circuit, or it is
picking up a computer diagnostic pulse, triggering the alarm.

Can you tell me what is "going off"?

If this is an aftermarket system, maybe I can help.
If it's a factory system, then I am afraid the service
department at Mazda is your next step. They shiould rund
a diagnostic to locate and correct this issue.

Let me know which it is.

ALARMTEK