But on Thursday, the Martins pleaded guilty in federal court here to illegally purchasing hundreds of dogs for resale to research facilities including Johns Hopkins and Columbia Universities.
The Martins, who operated Chestnut Grove Kennel, admitted that they received hundreds of thousands of dollars from research facilities for fraudulently obtained dogs between 2005 and 2010.
Under a deal with prosecutors, Floyd Martin pleaded guilty to one count of mail fraud, for which he will serve a year in prison, while Susan Martin pleaded guilty to a count of conspiracy, for which she will be placed on probation.
The Martins also will be required to pay $300,000 in restitution.
The sentence will not be official until U.S. District Judge John E. Jones III reviews a presentence report ahead of a June 26 sentencing hearing. He could determine if a change in the sentencing is needed.
Assistant U.S. Attorney Michelle Olshefski declined to comment after the hearing.
Susan Martin's attorney, Lawrence Rosen, said only that the Martins were pleased that the case was behind them.
"It was very stressful for them," said Rosen as Susan Martin, 56, helped her husband from the courtroom. Floyd Martin, 57, has multiple sclerosis and other conditions, he told the court.
The case shed light on the shadowy world of dog-dealing for biomedical research.
"We're talking about an abuse-ridden system of acquiring animals for research," said Nancy Blaney, senior federal policy adviser for the Animal Welfare Institute, a national advocacy group. " 'Random source' is what it sounds like it is. They can get animals from individuals who respond to 'free to good home' ads or animals being stolen. We know because they have been traced through micro-chipping."
The guilty pleas come nearly a half-century after a Pennsylvania case involving a Dalmatian named Pepper, stolen from her family's yard and sold to a New York research hospital in 1965, first drew attention to the practice.
Before her owners could track her down, Pepper died as the result of a cardiac pacemaker experiment. But her story helped win passage of the federal Animal Welfare Act in 1966, establishing humane standards for animals in laboratory settings and regulating dealers that sold to them.
In 2011, when the Martins were indicted by a grand jury, they were among a handful of remaining Class B "random source" dealers in the nation. Three of the six dealers still licensed are under federal investigation.
Class B dealers may purchase dogs from unlicensed individuals who collect dogs - "bunchers" - but those individuals may sell the dealers no more than 24 dogs a year.
According to the indictment, the Martins purchased hundreds of dogs from just two individuals while falsely certifying to the U.S. Department of Agriculture that they had purchased fewer than 25 dogs from multiple family members and friends - including one person who was deceased by the time of the alleged sale.
Two coconspirators, who have not been charged, bought hundreds of dogs from different sources in 10 states and sold them to the Martins for $50 to $75 each, authorities say. The Martins then sold the dogs to hospitals and other research labs for hundreds of dollars in profit per dog, the indictment said.
About 3 percent of dogs used in biomedical research in the United States come from random-source dealers, federal data show. In 2010, that number dipped to 3,100, down from tens of thousands 15 years ago.
Many research facilities have moved away from use of random-source dogs, as attitudes on use of animals in testing has shifted and pressure has mounted against experimenting on animals that may have once been pets.
The National Institutes of Health said in 2011 that it would phase out use of dogs from Class B dealers by 2015.
Most labs that use dogs in research now buy from facilities where animals are bred for research.
Contact Amy Worden at 717-783-2584 or firstname.lastname@example.org or follow @inkyamy on Twitter.