Four members of the Mother Nature environmental group – Sun Ratha, Ly Chandaravuth, Yim Leanghy and Alejandro Gonzalez-Davidson – were charged on Sunday, according to pro-government local media, with plotting and insulting the king (lèse majesté) under Articles 453 and 437(bis) of the Criminal Code, which carry maximum sentences of 10 years and 5 years, respectively.

Ratha and Chandaravuth were arrested alongside another activist, Seth Chhivlimeng, in Phnom Penh. The three were arrested on Wednesday morning, apparently in relation to their activities documenting runoff draining into the Tonle Sap river in the capital’s Daun Penh district. Chhivlimeng was later released from detention after being detained for 24 hours at the Police Private Security Management department of the Ministry of Interior, while Ratha and Chandaravuth remained in detention.

Also on Wednesday, police in Kandal province’s Koh Thom district summonsed environmental activist Yim Leanghy for questioning and he was arrested after arriving at the police station. He was later transferred to Phnom Penh and was sent to court along with Ratha and Chandaravuth. Leanghy, Ratha and Chandaravuth face between 1 and 5 years in prison for insulting the king as well as a fine of between 2 and 10 million riel ($500 to $2,500), and they also face between 5 and 10 years in prison for plotting. Also charged with the same crimes was Spanish national Alejandro Gonzalez-Davidson, who was deported from Cambodia in 2015 in relation to his activities as the co-founder of the Mother Nature Cambodia environmental movement.

Leanghy is a 32-year-old student who obtained a scholarship to study for a Master’s degree at the Royal University of Phnom Penh’s Institute of Foreign Languages. Ratha is a 26-year-old accountant who graduated from the University of Cambodia, where she was also studying on a scholarship. Chandaravuth is a 22-year-old law student in his 4th year of studying law at the Royal University of Law and Economics.

Last month, the Phnom Penh Municipal Court sentenced three other imprisoned environmental activists associated with the Mother Nature movement to between 18 and 20 months in prison for organising a peaceful, one-woman march to highlight the filling-in of Phnom Penh’s Boeung Tamok lake. Two other Mother Nature members, Alejandro Gonzalez-Davidson and Chea Kunthin, were also sentenced in absentia at the time.