Congo Republic jailed a notorious poacher for 30 years for ivory trafficking and the attempted murder of park rangers, a conservation group said, hailing the case as a milestone in the fight to hold wildlife criminals to account.

Mobanza Mobembo Gerard, known as Guyvanho, led poaching expeditions in the central African country that may have killed over 500 elephants since around 2008, according to the Wildlife Conservation Society.

His trial and sentencing last week marked the first criminal conviction of a wildlife trafficker in Congo Republic.

Previously, environmental crimes were tried in civil courts and incurred a maximum sentence of five years, it said.

The sentence “sends an extremely strong message that wildlife crime will not be tolerated and will be prosecuted at the highest levels,” WCS regional director Emma Stokes said in a statement on Monday.

Congolese judicial authorities could immediately be reached for comment.