Strange image captured by gas station camera

This is truly happened in a American gas station.
It is reported by many tv stations.
The above one is just one of them.
So i don't think it can be a fake one.
Many people had witnessed what had happened on the video.
What is the blue image?
Why it stayed there for half an hour?
Many people believe it is a ghost...
Because it cannot been seen by eyes...
What do you think?
Many things happening around us can not be explained in science way...
But believe or not...
We have to confess that they really exist in our world...
They are may be around you now...