Madeleine Fedyk and her husband left their dogs at the facility for training while they were out of the country for three weeks.
Fedyk says within 48 hours, one of their dogs died.
She told Eyewitness News the trainer said their 2-year-old Bernese Mountain dog "Dunkin" had passed away due extreme heat while training at a local park.
"Dunkin was never taken to a vet... We weren't called for at least 4, 5 hours after he passed away," Fedyk said. "The story didn't really make much sense to us at the time, when he told us. But we now have a very different view of what has happened."
Fedyk added she's received other messages from other people who claim their dog also died in that trainer's care.
Eyewitness News has reached out to the trainer and the facility for comment. We aren't naming the company until we hear back.