HAT YAI, Thailand — He had already endured a treacherous journey down the Bay of Bengal, squeezed in the belly of a fishing trawler, then squashed in a pickup truck as it hurtled down Thailand’s southern coast. Malaysia, his final destination, was tantalizingly close.

But under the towering trees of a rubber plantation, the smuggler who had brought Abdul Musid, a 30-year-old from Myanmar’s Rohingya Muslim minority, this far made a new demand: Pay more or be left behind. When Mr. Musid pleaded that he had no more money, the smuggler kicked him in the groin and left him for dead.

A villager found Mr. Musid and brought him to the hospital here for treatment, doctors said, after the other captives in the smugglers’ camp, also Rohingya men from Myanmar, fled with their jailers before a raid by the Thai authorities.

Violence by the Rakhine ethnic group, driven by an extreme Buddhist ideology, has led tens of thousands of Rohingya to flee in the last 18 months through smuggling rings that pledge to take them to Malaysia, a Muslim country that quietly accepts the desperate newcomers.