BANGKOK — When the authorities in Thailand recently intercepted huge stashes of ivory stuffed inside shipments of beans and tea leaves, the seizures were described as groundbreaking international police work.

Europol, the international police agency, said the sting operation that led to them was “the biggest ever coordinated international law enforcement operation targeting the illegal trade in endangered species.”

But there was a major omission in the operation, which took place over the past four months and uncovered more than 1,300 elephant tusks: There was no cooperation with and no arrests in the country to which the ivory was being shipped, Laos, a thinly populated Southeast Asian nation that shares a border with Thailand and in recent years has become a major transit point for a variety of exotic and endangered animals.

Many countries across the world have enhanced their campaigns against wildlife trafficking syndicates that are draining Asia’s jungles and the African savanna of elephants, rhinoceroses and other animals, many of them considered choice foods in parts of Asia. But Laos, which is run by a secretive and authoritarian communist government, stands out as a bastion of impunity, say those involved in the crackdown.