Three Mother Nature environmentalists were charged on Monday and placed in pretrial detention at Phnom Penh’s Prey Sar prison, as the mother of one of the activists said she was in shock but buoyed by support on social media, including from celebrities.

Sun Ratha and Yim Leanghy were charged with plotting, which carries a jail term of five to 10 years, and insulting the king, punishable by one to five years. Ly Chandaravuth was charged with plotting, according to municipal court spokesperson Y Rin.

Ratha was placed in pretrial detention at Correctional Center II, and Leanghy and Chandaravuth at Correctional Center I, Rin said.

A fourth activist was also arrested in Phnom Penh but has been released.

Ly Chanavy, Chandaravuth’s mother, said she could not see her son’s face at the court on Monday as he had been brought in through a back entrance. But she had earlier seen all three smiling as they were transferred to and from the court, she said.

“They smiled with tears,” Chanavy said.

She was uplifted by seeing strong support for them on social media, she added.

Thierry Chantha Bin, a France-born footballer on the Cambodian national team, shared a post about the activists with emoji of an upheld fist, Cambodian flag and a sproutling. Comedian Peypey Dy also shared the post.

Singer Kesorrr said: “Hope to get further information and hope that nothing bad happens to them.” Singer Jenny Vee added a message: “Can we join hands together one more time?” #justice4all #justice4Rotha #justice4Daravuth #justice4Leanghy”

“Although I’m upset and shocked, I get power from them, because people who have never paid attention to the environment before and never shared [about it], this time they’re sharing and posting, including singers and a footballer,” Chanavy said.

She said the three arrested environmentalists, including her son, had shown bravery.

“He told me that what he has done for society is [for] a clean environment, no polluted water and no impact on biodiversity, and for people’s health and to keep the forests — he thought this was not wrong,” Chanavy said.

The activists were filming sewage discharge on Phnom Penh’s Riverside at the time of their arrest. On Facebook, Mother Nature posted photos of the activists advocating for environmental issues.

Am Sam Ath, deputy director at rights group Licadho, said Mother Nature’s deported co-founder, Alejandro Gonzalez-Davidson, was also charged with plotting and insulting the king.

The charges against the environmentalists were severe, Sam Ath said. “We see these charges as a serious threat and intimidation for youth that love and protect the environment and natural resources — this is to break their spirit.”

Interior Ministry spokesperson Khieu Sopheak alleged last week that the group was using environmental issues to try to topple the government.

Three other Mother Nature activists were arrested for incitement last September and sentenced to 18-20 months in jail last month. The latest arrests came just a week after the U.S. ambassador met with Interior Minister Sar Kheng over previous prosecutions against environmentalists.