Aftermarket Alarm wont go off

[sr79]

I think my girlfriend's 2016 HRV has an aftermarket car alarm installed as there is a device near the break mounted to the plastic. The device is small, the size of half a pack of cigarettes and has a little button and a blue flashing light. Tonight whenever she used the FOB to lock the car, the alarm kept going off. Our solution tonight was just to leave the car unlocked. Any idea what could be wrong or how to disable it? The device had a cluster of wires running to it that look like they could be unplugged but i was nervous to try. The device had no discernible marking on it so i am not sure how to determine the manufacturer. Any ideas would be appreciated.