John Hume, the South African who bred the world’s biggest rhino herd, has been arrested on charges of smuggling 250 million rand ($14 million) worth of the endangered animals’ horns.

Hume, 83, was arrested on Tuesday alongside five other people including former employees at his ranch, a lawyer and the head of a rhino-focused nonprofit, South Africa’s National Prosecuting Authority said in a statement. They were charged with fraud, theft, and contravention of the National Environmental Management: Biodiversity Act, with additional charges of racketeering and money laundering under consideration, the country’s environment department said in a separate statement.

"The syndicate is linked to a fraudulent scheme involving 964 rhino horns, worth millions of rands, destined for illegal markets in Southeast Asia,” the environment department said in a statement. "The suspects allegedly defrauded the Department of Forestry, Fisheries and the Environment by securing permits under false pretenses to buy and sell rhino horns domestically, while funneling them into illegal international markets.”

In Southeast Asia, ground rhino horn is believed, erroneously, to cure ailments including cancer.

Hume, over a period of more than a decade, bred a herd of about 2,000 white rhinos, or an eighth of the global population, at a ranch near Klerksdorp, which lies 155 kilometers southwest of Johannesburg.

He sold the ranch and rhinos to African Parks, a billionaire-backed conservation nonprofit, in 2023 after years of unsuccessfully campaigning for the legalization of international trade in the animals’ horns. He argued that this would cut poaching as rhinos can regrow their horns after having them cut off. While they can be traded within South Africa, there is no demand.

The arrests followed a seven-year investigation by a wildlife trafficking unit of the police. Tammy Hume, Hume’s daughter-in-law and spokeswoman, declined to comment when contacted. He was released on a 100,000 rand bail.

South Africa is home to about 80% of the world’s rhinos and has lost hundreds of the animals annually to poachers for at least the last 15 years.