How could I find out the breed of my dog?

My dog was very smart, he was around 80 pounds, totally has no interest and offensive to other people, only loves the family members, he seldom barks except he found something wrong, he is protective if someone shows dangerous behaviors. He did not like other puppies, even bite them sometimes if other puppies try hard to play with him, we have to keep him away from other dogs, except that, his personality is perfect for us.

He was from Kazakstan and lived with us for 6 years, we missed him very much, and we like his personality very much. We have lost him for almost 10 years, and we still brought him up occasionally.

What’s another sorry is that we did not know what’s the breed of him, how can I find out what’s the breed of my dog?

When he was 6 months old.

When he was 6 months old.

When he was 2 years old.