the dementor: alive or dead?

[severusbook4]

No: HPFGUIDX 80494

I believe that a dementor is possibly a human that has received the 
kiss.  But this has been taken one step further by the wizarding 
people.  They resemble humans in form, and human traits, breathing, 
walking upright, etc.  Isn't there canon to support that they are a 
creation of the wizarding world?  Not a creature that roams freely?  
If you think about it, wouldn't a souless human pocessed of 
unnatural life, continuously seek which it didn't have? A soul, no 
matter if it wasn't their own or not?  They are discribed as looking 
diseased and rotting. Just a thought.  Feel free to destroy.

Sevvie