"This was just a little glitch." false alarm?

What in the world does this error mean? My alarm triggered and, according to the police whose time I wasted, there was no evidence of a break-in attempt. I don't feel comfortable turning my own sensor back on when it is just constantly falsely detecting motion. Edit: half an hour later after the police were here and the sensor hasn't stopped detecting motion despite there being plenty of opportunities for it. No other sensors are going off.