Infamous Theft System Problem- Car May Not Restart
 

I just picked up an immaculate 99 DeVille D'Elegance from police siezure. Car has sat inside PD garage while going thru court system. Battery is dead. When trying to jump you get the theft message. Before I go tearing into things is it possible a completely drained battery can cause this? PD said on night of siezure car ran perfectly. New to caddy's, so looking for advice. Thanks!