"When we asked she said, 'Oh, he's just a runt. He was a little tiny. He didn't get as much milk,'" Tiffany added.
The Bertoni's say Dexter's weight dropped from eight to four pounds. That's when they confronted the breeder again.
"She said at that point, 'Well, he did have hook worms and we were treating it,'" said Antonio.
TODAY'S TMJ4 contacted the breeder, Haley Knighten in Oklahoma to get answers. She called back and agreed to talk on a recorded line:
Haley Kingston: That's normal for puppies to have, they come like that from their parents.
Julia Fello: Your puppies always have worms?
Haley Kingston: It's normal for puppies to have worms. That's why you worm them every either once a week or either two times, every two weeks.
Julia Fello: This misunderstanding cost the dog his life.
Haley Kingston: Yes I know and I'm very sorry for that and I told her that and I have been really upset about it
The couple paid $2,700 for a blood transfusion to save Dexter's life. Doctors realized he had another parasite, called Coccidia. He died in their arms Sunday on the way to the vet.
TODAY'S TMJ4 spoke to Veterinarian Libby Gutting at the Milwaukee Area Domestic Animal Control Commission, who is not connected to the case. She says reputable breeders should see a vet routinely to start vaccines and a deworming protocol before selling. The buyer then would be responsible for continued boosters.