PHOENIX -- Carcasses of 124 greyhounds have been uncovered in a citrus grove, spurring accusations by animal-rights activists that the dogs were victims of cruelty rampant in Arizona's racing industry.

Authorities said the perpetrator could be prosecuted for criminal littering but might not be liable for the deaths because owners are allowed to kill their animals according to the legal standard for humane death -- that the animal dies instantly. Most of the dogs' left ears, which bear their registration numbers, were missing.

Crews at Empire Fruit Co. in Chandler Heights, a nearby farming community, began finding unburied dogs last week as they removed trees from a 240-acre grove unused for several years. The animals were buried Thursday in a pet cemetery.

Authorities said the greyhounds, found in various stages of decomposition, apparently were dumped after being shot or bludgeoned in the head. Authorities said the carcasses had been in the grove from 10 days to six months.

Greyhound racing is permitted in 19 states and produces an estimated $30 million a year in Arizona.

Disposing of greyhounds whose racing careers have ended has been a recurring problem for the industry. Some greyhound racing parks have increased efforts to encourage adoption of the gentle, frisky dogs.