Four foreign men have been executed in China for murdering 13 Chinese fishermen on the Mekong River in 2011.

Accused ringleader Naw Kham and accomplices Hsang Kham, Yi Lai, and Zha Xiha were found guilty of the murder of 13 Chinese fishermen in an Oct. 5, 2011, attack on the Mekong River. The four are of Myanmar, Thai, Laotian, and unknown nationality.

They were put to death by lethal injection in Kunming, the capital of Southwest China’s Yunnan province.

State media said Naw Kham, a Burmese, is thought to have been the most powerful warlords in the Golden Triangle of Thailand, Laos and Myanmar. Naw Kham and his subordinates had collaborated with Thai soldiers in launching an attack on the ships, the Hua Ping and Yu Xing.

The state-run China Central Television News broadcast live footage of the men being taken from their cells to the execution site, though it did not show the moment of death, which the Associated Press comments “a throwback to the mass public execution rallies of past years.”