In life, we always have a way of finding things out. As the saying goes, we live and we learn. We learn who our true friends are whenever we are in sticky situations. We learn who we and cannot trust and it is sad because you think that the person that you always call  'chomi' or 'friend' is really your friend only to realize that no and when you need them most they will not be there for you. 
Even though I am so old I have recently found this out for myself. I guess a dog is never too old to be taught new tricks.