Prosecutors in Thailand have recommended charges against more than 100 people, including an army general, in connection with a probe triggered by the discovery earlier this year of some 30 gravesites near the country's southern border containing the remains of migrants from Bangladesh and Myanmar.
Malaysia later uncovered 139 more graves on its side of the Thai-Malay border.
The plight of the migrants was further illuminated by the weeks-long saga of Muslim Rohingyas from Myanmar adrift at sea and refused entry by several countries in Southeast Asia, including Thailand.
Office of the Attorney General spokesman Wanchai Roujanavong was quoted by The Associated Press as saying 91 Thais, nine Myanmar nationals and four Bangladeshis face 16 charges, including human trafficking, participating in an international crime network and transporting aliens into the country.
"The investigation showed it is a big syndicate. There were networks that brought them (the migrants) from overseas into the country systematically," the spokesman said. "There were a lot of damages. Bodies were found. Senior officials were accused, as well as influential figures. The Office of the Attorney General, therefore, treats it as a very important case."
The AP quotes the spokesman as saying: "15 state officials, including Lt. Gen. Manas Kongpaen, four policemen, a powerful provincial mayor and local politicians, will also face charges of negligence of their duty. He said provincial prosecutors have pressed charges against 72 arrested suspects and were waiting to proceed with 32 others who remained at large.
Earlier this month, Kongpaen turned himself in to police in the Thai capital, Bangkok, but denied accusations that he was involved in human trafficking.