Mariango was arrested in October 2015 with his brothers Lucas Mathayo Malyango and Abdallah Ally Chaoga while attempting to smuggle 118 tusks worth over $863,000.

Aged 47, Mariango was one of the poachers featured in the Netflix documentary film, The Ivory Game, produced by Hollywood actor Leonardo DiCaprio.

He also stands accused of supplying ivory to Yang Feng Glan, a Chinese national nicknamed “Queen of Ivory,” who is on trial in Tanzania for smuggling ivory worth $2.5 million.

On March 3, a Tanzanian court sentenced one of the country’s most wanted elephant poachers to 12 years in prison.

Boniface Matthew Mariango, nicknamed “The Devil” by law enforcement officials (or “Shetani” in Kiswahili), stands accused of killing thousands of elephants and of having links to 15 poaching gangs in five countries: Tanzania, Burundi, Zambia, Mozambique and southern Kenya.

He was arrested in October 2015 with his brothers Lucas Mathayo Malyango and Abdallah Ally Chaoga while attempting to smuggle 118 tusks worth over $863,000. Tanzania’s National and Transnational Serious Crimes Investigation Unit (NTSCIU) caught the men on the outskirts of Dar es Salaam after a manhunt that lasted over a year.

Mariango, aged 47, was one of the poachers featured in the Netflix documentary film, The Ivory Game, produced by Hollywood actor Leonardo DiCaprio.

“WWF congratulates the Tanzanian authorities involved in Shetani’s arrest and successful prosecution,” Amani Ngusaru, WWF-Tanzania Country Director, said in a statement. “Poaching elephants for ivory is robbing Tanzania of its heritage. This prosecution sends out a strong message that Tanzania’s authorities are taking it seriously and are working to eliminate poaching in the country.”

Mariango has a few other pending cases against him. He also stands accused of supplying ivory to Yang Feng Glan, a Chinese national nicknamed “Queen of Ivory,” who is on trial in Tanzania for smuggling 706 elephant tusks with a street value of $2.5 million in 2015.

“This sentencing is a message to the people that the government of Tanzania is serious, and is going to catch and make sure that the big guys are prosecuted,” Robert Munde, Assistant Director of Tanzania’s anti-poaching unit, told CGTN Africa.

About 30,000 African elephants are killed for their ivory every year, with Tanzania being one of the worst affected areas. A recent report found that the country lost 60 percent of its elephant population in just five years, between 2009 and 2014.

China is one of the world’s biggest markets for ivory. But in December last year, the Chinese government announced that it would close its domestic commercial ivory market by the end of 2017, a move conservation groups have called a “game-changer” for elephants.