Officers with the New Jersey Society for the Prevention of Cruelty to Animals said they found the puppies, recently purchased from two of Pennsylvania's largest puppy mills, in filthy crates stacked on top of one another in the unventilated closet in Franklinville.

"They were very sick," said Sy Goldberg, lieutenant colonel of the NJSPCA in New Brunswick. "They were lethargic. They had pus coming out of their noses and swollen eyes."

The dogs were taken to the Columbus Animal Hospital in Burlington County for treatment of pneumonia, hookworm, and other highly contagious diseases.

Officers arrested William J. Roberts, 57, and charged him with the fourth-degree criminal offense of willfully selling an animal with a contagious disease.

Roberts, who was released on bail, faces up to three years in jail and a $7,500 fine if convicted. He also faces multiple animal-cruelty charges on allegations that he failed to provide adequate care.

The NJSPCA will also recommend to federal and state agencies that they file charges relating to tax fraud and dispensing prescription drugs without a license, Goldberg said.

The puppies - all 6 to 10 weeks old - included West Highland terriers, Pomeranians, golden retrievers, and Yorkshire terriers.

They were among the 40 to 50 dogs Roberts sold each month for an average of $400, officials said.

Roberts had been operating for at least six years as an underground broker, buying puppies from kennels in Lancaster County, stashing them in his home, and selling them out of his car, officials said.

He regularly placed ads in The Inquirer and other newspapers. His cash-only sales often took place in parking lots and netted him $200,000 a year, officials said.

The NJSPCA launched its investigation with an undercover agent three weeks ago after five consumers who bought sick puppies from Roberts complained.

Records seized in the raid showed Roberts had bought dogs from Pennsylvania breeders Nathan Myer and David Zimmerman, both of whom sell hundreds of dogs a year.

Myer, a former member of the state Dog Law Advisory Board, has been cited for numerous dog-law violations in the last year.

Zimmerman, reached by phone at his kennel in Ephrata, said he did not recognize Roberts' name. Asked whether he sold healthy dogs, he said: "We try to."

It was unclear whether any charges will be brought against the breeders in Pennsylvania. Lancaster County Assistant District Attorney Christine Wilson said yesterday that she would have to review the case before commenting.

Roberts has a history of problems relating to dog breeding and sales dating to mid-1990s, and was well-known to a group called New Jersey Consumers Against Pet Shop Abuse.

"He preyed upon naive consumers," said group founder Libby Williams, who has tracked complaints about Roberts since 2002. "The puppy prices were cheaper than breeders and pet shops, and he was selling sickly animals."

Williams estimated that a dozen underground dog brokers operated in New Jersey.

The NJSPCA is seeking donations to help care for the 28 rescued dogs. Its Web site is www.njspca.org.