LOS ANGELES, Calif. — A father and son are expected to be sentenced to federal prison terms today for their roles in the illegal trafficking of South African rhinoceros horns in a case brought as part of a nationwide crackdown on the black market in endangered animal parts.

Vinh Chuong “Jimmy” Kha, 50, and Felix Kha, 27, both of Garden Grove, each pleaded guilty in Los Angeles last year to five felony counts — conspiracy, smuggling, wildlife trafficking in violation of the Lacey Act, money laundering and tax evasion — stemming from the smuggling conspiracy, according to the U.S. Attorney’s Office.

A third defendant — Win Lee Corp., a Westminster company owned by Jimmy Kha — pleaded guilty to smuggling and wildlife trafficking and is also scheduled to be sentenced today.

Federal prosecutors are asking U.S. District Judge Christina A. Snyder to sentence Jimmy Kha to almost five years behind bars and his son to nearly six years, and order them to each pay $100,000 in fines. The government is also requesting that the Win Lee Corp. be fined $100,800 over a five-year period of probation.

“It is unconscionable that a species as ancient and majestic as the African Black Rhino has been hunted to the brink of extinction by unscrupulous profiteers,” U.S. Attorney Andre Birotte Jr. said after the men pleaded guilty.

“The rhino horn smuggling ring, dismantled by ‘Operation Crash,’ contributed to the soaring increase in the trade of rhino horns both domestically and internationally, and this illegal trade leads directly to increased poaching of the species in the wild,” he said.

In Vietnam, where it sells for about $1,400 an ounce, powdered rhino horn is rumored to cure cancer, improve general health and prevent illness. It is also used to treat dozens of ailments, including hangovers, according to Traffic, the wildlife trade monitoring network.

In their plea agreements, the Khas each admitted purchasing white and black rhinoceros horns, knowing the animals were protected by federal law as endangered and threatened species. Both defendants admitted they purchased the horns to export them overseas so they could be sold and used as medicine.

The Khas also acknowledged bribing Vietnamese customs officials to ensure clearance of horns sent there, and admitted they failed to pay income taxes for 2009 and 2010.

In sentencing papers, federal prosecutors contend that in 2008, the demand for rhino horn in China and Vietnam began to increase after a 20-year period of low poaching rates in South Africa, where the animals originate.

Seeing the developing market, the Khas “knowingly chose to illegally supply rhino horn to meet the growing demand, thereby simply increasing that demand,” prosecutors wrote, calculating that the men “helped to drive the commercial value of rhino horn from a very low level to nearly $25,000 per pound.”

The increasing commercial value of rhino horn in turn “drove the poachers back into the wild savannas of South Africa and other African countries in search of irresistible profits,” according to court papers.

“By the peak of defendant Jimmy and Felix Khas’ wildlife trafficking conspiracy in 2011, 448 wild rhinos had been slaughtered for their horns in South Africa alone.”

Two other defendants linked to the Khas — Jin Zhao Feng, 47, of China, and Jarrod Wade Steffen, 34, of Hico, Texas — previously pleaded guilty in Los Angeles federal court to charges related to rhino horn trafficking.

When he pleaded guilty last year, Feng admitted he attempted to smuggle a horn from an endangered black rhinoceros from the United States to China. He was sentenced to time served.

Steffen, who used money provided by the Khas to buy horns for them, pleaded guilty to conspiracy, smuggling, wildlife trafficking and money laundering. He is scheduled for sentencing in October.