In cities across the US, police dogs working the crime beat have usually been purebreds, trained in Europe, at a cost of tens of thousands of dollars for police departments.

But trainer Brad Croft in San Antonio, Texas, has shown that law enforcement can get the same work for next to nothing by simply turning to the countless future K9s that are on "doggie death row" in US shelters.

"All they need is a chance to prove themselves and these dogs will work every bit as hard as the purebred dogs that we bring in from overseas," said Croft, the founder of Universal K9.

Related: Touching surprise procession for fallen hero K9 officer. Related: Group seeks to arm K9s with bulletproof vests.

Croft and his mostly military trained staff have rescued 60 dogs so far this year from shelters across the South. They've trained the dogs in drug and explosives detection, scent tracking and other work. Once they're fully trained, the dogs are then delivered to local police departments for free.

"Right now, we're on track to saving almost 100 dogs this year [from euthanasia]," Croft said. "If you look at the statistics, the statistics are like something like 945,000 a year that are being euthanized."

Universal K9 currently has 15 dogs in its eight-week class.

Sadie, a 5-month-old mixed breed that was picked up off the street by animal control workers, is the class' star student.

"I found Sadie on the side of the road one day," said Estephen Centeno, an animal control worker in Kirby, Texas. "She was just so playful. She had a lot of energy in the beginning. … Hearing Sadie is like a miracle dog. … It's an amazing feeling because a lot of these dogs get put down in other places."

And the dogs aren't just joining police departments; they're also becoming members of police families.

WN from shelter to k9

Cpl. Wesley Keeling, an officer with south Dallas' Midlothian Police Department's canine unit, said his reluctance to take on K9 partner Remi, a graduate of Universal K-9, quickly turned into love at first sight. They've now been together 2.5 months.

Keeling said Remi was responsible for searching cars and buildings for narcotics as well as tracking people who may flee or who may go missing.

"Remi is a saved dog," Keeling said. "She's proud of herself. I'm proud of her. … She's wonderful. I can't say enough about her, I really can't."