Police on the border seized 33 workers returning from Thailand recently and took $42,000 for their release, the rights group Adhoc said Wednesday.

Sum Chankea, an investigator for the group, said police in Bantey Meanchey province arrested a group of men and forced them to empty a bank account of Thai baht worth $42,000, after arresting them on allegations of illegal border crossing.

One of the detained said a group of workers had pooled their money into one account for fear of it being confiscated by police.

"This more than 1 million baht is the sum of money collected by 33 workers from Thailand who deposited it in one account," Sum Chankea said.

Police charged one man with illegally bringing Cambodian workers into Thailand, he said, but the money was never returned.

Bantey Meanchey's Ochroy District Police Chief Oeung Song You said the provincial police chief had ordered them now to return the money to the workers.

"We're not taking the money," he said.