Seven people have been arrested on charges of trafficking in endangered rhinoceros horns in Los Angeles, New Jersey and New York over the past week, federal officials have said.
Four of the defendants were arrested in Los Angeles, with the latest arrest taking place at Los Angeles International Airport on Wednesday night, said US attorney's office spokesman Thom Mrozek.
Jin Zhao Feng, a Chinese national, was taken into custody at the airport. Authorities suspect him of overseeing the shipment of dozens of rhino horns from the US to China.
Special agents of the US Fish and Wildlife Service and US Immigration and Customs Enforcement Homeland Security Investigations made the arrests and served search warrants in as many as five states, according to a statement from the US Justice and Interior Departments.
The arrests were the result of an 18-month investigation called Operation Crash - the term for a herd of rhinoceroses - and scrutinised an international smuggling ring which trafficked in sawn-off rhinoceros horns. The horns are used by some cultures for ornamental carvings, good luck charms or perceived medicinal properties.
Three of the alleged traffickers caught in Southern California were Jimmy Kha, 49, his girlfriend Mai Nguyen, 41, and Kha's 26-year-old son Felix. Each faces four counts of rhino horn trafficking in violation of federal laws protecting rare and endangered species. One of the alleged suppliers, Wade Steffen, was arrested in Hico, Texas, and charged in Los Angeles, federal prosecutors said.
The Khas began receiving packages from Steffen and another alleged supplier in 2010. Seventeen packages were opened under federal search warrants and 37 rhinoceros horns were found, according to a criminal complaint filed in US District Court in Los Angeles.
A search of Steffen's luggage at the Long Beach Airport on February 9 turned up 337,000 US dollars (£215,000) in cash. Additional searches by federal agents found rhinoceros horns, cash, bars of gold, diamonds and Rolex watches. Approximately 1 million US dollars (£637,250) in cash was seized and another 1 million US dollars worth of gold nuggets, federal officials said.
"The rhino is an animal of prehistoric origin that is facing possible extinction because of an illegal trade for its horns on the black market that is driven by greed," said Ignacia S Moreno, assistant attorney general for the Justice Depatment's Environment and Natural Resources Division.
The arrests were initially reported by the Los Angeles Times. In New Jersey, Amir Even-Ezra was arrested on February 18 on a trafficking charge after purchasing rhino horns from a New York resident in New Jersey. Antiques expert David Hausman was charged in the US District Court in Manhattan with illegally trafficking rhinoceros horns and with creating false documents to conceal the illegal nature of the transaction, prosecutors said.