Maybe he had an external PIR added to it or it was external IR?
Many models come with extra wires for alarms, inputs, outputs, etc., so you could set something up like that, but then that device would need power as well.
And you don't know at what other parameters he was running at - you could set the camera up with a 1/12 shutter speed and it would see stuff even without the IR, but it will be a motion blur then when there is motion.
