Police said they would file animal-cruelty charges this week against Stevenson, who was characterized by a U.S. Humane Society investigator as ''not hard-core, but not an amateur either" in the world of dog fighting. An animal-cruelty charge is a summary offense, punishable by a $300 fine and a 30-day jail term.
Stevenson could not be reached for comment.
Police said they seized photographs of dogs, many of them bloody and scarred, and a "breaking stick" - a knifelike device used to pry open the jaws of the dogs to separate them during a fight.
Agents with the Bucks County Society for the Prevention of Cruelty to Animals (SPCA) confiscated two scarred pit bulls as evidence, police said.
Underground dog-fighting magazines dating back three years were found, some containing advertisements for the sale of pit bulls by Stevenson and results from fights allegedly held at his home, police said.
The magazines, with such names as Sporting Dog Journal and Game Dog Digest, are available only upon the recommendation of a current subscriber, according to Anne Irwin, executive director of the SPCA.
Irwin said the SPCA considered the dog fights among the worst forms of animal cruelty. The fights can last as long as five hours, she said, and the dogs are trained to continue fighting beyond injury or exhaustion. Cockfights are generally fought to the death, she said.
The 9 p.m. raid took place within hours of a raid of a West Philadelphia house, where police said preparations for an invitation-only dog fight appeared to be under way.
Stevenson was believed to have been on his way to Philadelphia to observe that fight when his home was raided, said Paul Miller, a field investigator with the Humane Society who accompanied Bucks County agents to Stevenson's home.
The investigation, conducted by Bedminster Township and state police at the Dublin Barracks, began about seven months ago, when neighbors complained about the number of dogs and the traffic at the home, said David J. Stevens, a Bedminster Township detective.