In mid-2012, Beehive Radio reported on an
International Court of Justice complaint against Prime Minister Hun Sen blaming him for the 2010
Phnom Penh stampede, in which 347 people were killed. The report sparked a new series of disputes between Sonando and Hun Sen. On the final day of the protests, soldiers opened fire on a crowd of families, killing a 14-year-old girl. Though Sonando returned during the 2012
ASEAN meeting, he was not arrested until 15 July, a few days after its end. The charges carried a maximum sentence of 30 years in prison. Secessionist charges were also brought against several community activists from the province. On 22 July, he was moved to a prison hospital on account of illness. CPJ called for Sonado's immediate release, stating that Hun Sen had "a well-worn history of leveling unsubstantiated anti-state charges against journalists to stifle criticism of the administration." The
International Federation for Human Rights and the
World Organisation Against Torture issued a joint statement noting that they were "gravely concerned" about the charges and calling for Sonando's immediate release.
Reporters Without Borders described the arrest as "like a parting slap to all those who attended last week's ASEAN summit in Phnom Penh. As soon the diplomats leave, the authorities arrest dissidents." The Ireland-based NGO
Front Line Defenders included him on the short list for its 2013 Human Rights Defender at Risk award. On 1 October 2012, Sonando was found guilty by a Phnom Penh court. He was sentenced to twenty years' imprisonment and fined 10 million riel (US$2,500). In November, US President
Barack Obama raised concerns about the case during a meeting with Hun Sen. French Prime Minister
Jean-Marc Ayrault also called for Sonando to be released. An appeals court overturned Sonando's conviction on anti-state charges on 14 March 2013, finding that there had been no evidence to convict him. The court instead gave Sonando a five-year suspended sentence on charges that he had been involved in the Kratié unrest. A crowd of hundreds of Sonando supporters gathered outside the courthouse to hear the verdict. Amnesty International called the ruling "a positive step for freedom of expression in the country", but added that "Mam Sonando should never have been imprisoned in the first place, and the convictions that stand appear baseless." Sonando was released from prison on 15 March, the day after the ruling. Following his release, Sonando stated his intention to clear his name of the remaining charges. ==2014 protest==