This is a quote from the Illinois Digest Of Hunting And Trapping Regulations 2003-2004.

ILLINOIS STATEWIDE DEER HUNTING iNFORMATION
PAGE 10.

" White Deer Protected "
IT IS UNLAWFUL to take any all white- Whitetailed deer at anytime.

So if this deer was taken by a hunter engaged in the act of hunting in the state of Illinois is was taken ILLEGALLY, IF IT IS A ALL WHITE DEER OR A ALBINO WHITETAILED DEER.