Not all ghosts are dead. It is entirely possible to see the ghost of someone living. Ghosts are made up of the energy that we leave behind. The stronger the energy or the event the stronger the image left behind.
Of course living ghosts are more likely to be spotted by someone who knows the "ghost". We've all been there, out someplace and out of the corner of your eye you see someone you know. So you look again and their gone. Strong emotions tied to the event that took place there will make the imprint even stronger.
