Pima County animal welfare officials have euthanized nearly 100 pit bulls seized from a breeding operation suspected of supplying fighting dogs to rings across the nation, officials said.

The 94 dogs killed were among 110 sheriff's deputies seized from the owners of the Picture Rocks kennel in the Tucson Mountains during a series of raids in February.

Kennel owners Mahlon Thatcher Patrick and Emily Elizabeth Dennis have been indicted along with four others on 69 felony and misdemeanor counts alleging animal cruelty, dog fighting and failure to obtain licenses.

Their lawyers say Patrick and Dennis are legitimate breeders.

Besides the Picture Rocks kennel, three other breeding operations were raided, culminating a yearlong investigation that began when Pima County authorities were tipped off by Chicago police and the Humane Society of the United States. About two dozen dogs were seized in those raids.

The dogs euthanized Thursday had been held as evidence, but a judge gave permission for the action earlier this week. Seven already had been euthanized for medical problems, and nine were taken by animal rescue groups, but homes for the others couldn't be found.

Jenny Rose, a spokeswoman for the Humane Society, said she believes the county shelter did the best it could under difficult circumstances.

"Obviously, it's very unfortunate, but (Pima County) Animal Care did everything they could to place them," she said. "It's hard to say why there wasn't more interest. Those dogs really were the victims of their circumstances."

Leads in the case were developed after Chicago police stopped a vehicle with several fighting dogs last March, and information eventually led to Tucson. Humane Society officials also provided information concerning the possibility of a dog fighting ring near Tucson.

After the raids, investigators accused Patrick of being among the top three suspected dog fighting breeders in the country.

Authorities said they seized more than 50 weapons and training materials, as well as a device used to hold female dogs in place for breeding.