aggression towards new puppy and owners

Question
We took in an adult, male, mixed-breed stray dog several years ago. He was stout, all black, short haired with a black tongue.
After adding a puppy to our home, a German short-haired Pointer female, our male became aggressive. He attacked the puppy viciously several times. After the puppy received professional training, the attacks were less frequent. But, we kept the pup in a wire kennel to separate them when we were away for safety. Recently, the male, "Bear" attacked my husband who was his biggest admirer and companion. After the attack, our teenaged son tried to put the dog in another room and was attacked too. Both received numerous, deep bites to the hands and forearms. About a month later, Bear attacked our teenaged daughter's foot. Several days after that, I had just spent some time petting the dog and tried to get the dog into another room where he usually slept. He attacked me, shaking my arm as he had his teeth in my flesh. Bear does not seem to have any physical problems and gets just as much love and attention as before the new puppy's arrival. Before now, Bear had only growled at us and visitors a few times, when eating or when we would try to get him to go into the backyard. Should Bear be put down?

Answer
"Should Bear be put down?"

This is a question only you and your family can answer.  I would suggest contacting someone who has experience in aggression in dogs.  You can search for people on the following two websites.  I would interview them carefully, making sure they are qualified to help with aggressive dogs.

Int. Assn of Animal Behavior Consultants
http://www.iaabc.org/suchen/

APDT trainer search
http://www.apdt.com/po/ts/default.aspx

I would also suggest you read this article:

http://www.aspcabehavior.org/articles/49/aggression-in-dogs.aspx