Updated

An international human rights group is urging Thailand to investigate the slaying of an environmental activist who exposed the dumping of toxic waste. It is also calling for better protection of human rights defenders in the country.

Village headman Prajob Nao-opas was shot dead in the eastern province of Chachoengsao on Monday. He had been campaigning for the past year against the dumping by factories.

Human Rights Watch said Wednesday that the Thai government should immediately bring those responsible for his death to justice regardless of their influence.

The group says more than 30 human rights defenders and environmentalists have been killed in Thailand since 2001.

Department of Special Investigation official Pongin Intarakhao said his team will provide information to help investigators in the case.